A158284 List of pairs p, p+2 where p is prime and p and p+2 contain the same number of prime digits.

3, 5, 5, 7, 13, 15, 23, 25, 29, 31, 43, 45, 53, 55, 73, 75, 83, 85, 89, 91, 103, 105, 109, 111, 113, 115, 163, 165, 173, 175, 193, 195, 223, 225, 229, 231, 233, 235, 263, 265, 283, 285, 293, 295, 313, 315, 353, 355, 373, 375, 383, 385, 389, 391, 409, 411, 433

Offset: 1

Author

Juri-Stepan Gerasimov, Mar 15 2009

Keywords

• nonn
• base
• less

Comments

Prime digits are 2, 3, 5 or 7.

Crossrefs

Cf. A077800.

Programs

Mathematica

snpdQ[n_]:=Count[IntegerDigits[n],?PrimeQ]==Count[IntegerDigits[n+2], ?PrimeQ]; {#,#+2}&/@Select[Prime[Range[100]],snpdQ]//Flatten (* Harvey P. Dale, Dec 04 2017 *)

Extensions

(13,15) inserted, (23,25) inserted, and all other numbers replaced by R. J. Mathar, May 19 2010

Definition changed to match the terms by N. J. A. Sloane, Dec 03 2017