A036976 Becomes a prime if a 1 is inserted before each digit.

1, 3, 7, 9, 17, 23, 27, 39, 51, 63, 69, 81, 93, 119, 121, 127, 137, 161, 193, 199, 203, 209, 233, 271, 301, 311, 313, 323, 331, 337, 343, 359, 361, 367, 371, 373, 431, 439, 443, 451, 463, 469, 479, 481, 497, 503, 523, 557, 577, 583, 587, 607, 641, 661, 677

Offset

0,2

Links

Table of n, a(n) for n=0..54.

Example

E.g. 27 -> 1217 is prime.

Mathematica

Select[Range[700], PrimeQ[FromDigits[Join[{1}, Riffle[ IntegerDigits[ #], 1]]]]&] (* Harvey P. Dale, Jul 24 2012 *)

Crossrefs

Cf. A036977.

Sequence in context: A064194 A036978 A079464 * A230116 A361005 A031273

Adjacent sequences: A036973 A036974 A036975 * A036977 A036978 A036979

Keyword

nonn,base,easy

Author

N. J. A. Sloane.

Extensions

More terms from Erich Friedman.

Status

approved