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A036976 Becomes a prime if a 1 is inserted before each digit. 1
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 (list; graph; refs; listen; history; text; internal format)
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 A031273 A140118

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

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Last modified August 22 20:47 EDT 2019. Contains 326209 sequences. (Running on oeis4.)