Strong's numbers

σημεῖον G4592

sēmeîon

say-mi'-on

neuter of a presumed derivative of the base of σημαίνω; an indication, especially ceremonially or supernaturally:--miracle, sign, token, wonder.

σημεῖον, -ου, τό [in LXX chiefly for אוֹת ;]

a sign, mark, token;

(a) of that which distinguishes a person or thing from others: Mt 26:48, Lk 2:12, II Th 3:17 (cf. Deiss., LAE, 1532); seq. gen. epexeg., Ro 4:11; c. gen. obj., Mt 24:8, 30, II Co 12:12; c. gen. subj., Mt 16:3;

(b) a sign of warning or admonition: Mt 12:39 16:4, Lk 2:34 11:29, 30, I Co 14:22;

(d) of miracles and wonders (MM, xxii), regarded as signs of a divine authority: Mt 12:38, 39 16:1, 4, Mk 8:11, 12 Lk 11:16, 29 23:8, Jo 2:11, 18, 23 4:54 6:30 10:41 12:18, Ac 4:16, 22; pl., Mk 16:[17, 20], Jo 2:11, 23 3:2 6:2, 14, 26 7:31 9:16 11:47 12:37 20:30, Ac 8:6, I Co 1:22 (Lft., Notes, 162); the same ascribed to false teachers and demons: Mt 24:24, Mk 13:22, II Th 2:9, Re 13:13, 14 16:14 19:20; σ. καὶ τέρατα (τ. καὶ σ.; cf. Tr., Syn., § xci), Mt 24:24, Mk 13:22, Jo 4:48, Ac 2:19, 43 4:30 5:12 6:8 7:36 14:3 15:12, Ro 15:19, II Th 2:9; id. seq. καὶ δυνάμεις, II Co 12:12, He 2:4; σ. καὶ δυνάμεις, Ac 8:13; δ. καὶ τ. καὶ σ., Ac 2:22; σ. διδόναι, Mt 24:24, Mk 13:22.†

From G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922), in the public domain.

Shown in the King James Version (KJV), whichever translation you read in — it is the text these numbers are tagged against.

Mark 8:12
And he sighed deeply in his spirit, and saith, Why doth this generation seek after a sign? verily I say unto you, There shall no sign be given unto this generation.
Mark 13:4
Tell us, when shall these things be? and what shall be the sign when all these things shall be fulfilled?
Mark 13:22
For false Christs and false prophets shall rise, and shall shew signs and wonders, to seduce, if it were possible, even the elect.
Mark 16:17
And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues;
Mark 16:20
And they went forth, and preached every where, the Lord working with them, and confirming the word with signs following. Amen.
Luke 2:12
And this shall be a sign unto you; Ye shall find the babe wrapped in swaddling clothes, lying in a manger.
Luke 2:34
And Simeon blessed them, and said unto Mary his mother, Behold, this child is set for the fall and rising again of many in Israel; and for a sign which shall be spoken against;
Luke 11:16
And others, tempting him, sought of him a sign from heaven.
Luke 11:29
And when the people were gathered thick together, he began to say, This is an evil generation: they seek a sign; and there shall no sign be given it, but the sign of Jonas the prophet.
Luke 11:30
For as Jonas was a sign unto the Ninevites, so shall also the Son of man be to this generation.