A246043 - OEIS

A246043

Biprimatic permutable numbers: Decimal numbers whose digits can be arranged to form exactly two prime numbers. No leading zeros.

13, 17, 31, 37, 71, 73, 79, 97, 107, 118, 119, 124, 125, 127, 128, 133, 139, 142, 146, 152, 164, 169, 170, 172, 181, 182, 191, 193, 196, 214, 215, 217, 218, 238, 239, 241, 251, 271, 277, 281, 283, 293, 313, 319, 328, 329, 331, 346, 347, 349, 356, 364, 365, 367, 368, 374, 376, 382, 386, 391, 392, 394, 412, 416, 421, 436, 437

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OFFSET

1,1

COMMENTS

In base ten these numbers can be said to have a prime twin made up of the same digits.

LINKS

Andreas Boe, Table of n, a(n) for n = 1..14440

EXAMPLE

170 -> 017 (forbidden), 071 (forbidden), 107 (prime), 170 (even), 701 (prime), 710 (even) -> conclusion: Two primes numbers.

MATHEMATICA

Select[Range[500], Count[FromDigits/@Select[Permutations[IntegerDigits[#]], #[[1]] != 0&], _?PrimeQ]==2&] (* Harvey P. Dale, Oct 23 2018 *)

CROSSREFS

A245808: Monoprimatic permutable numbers

A246044: Monoprimatic permutable primes

A246045: Biprimatic permutable primes

Sequence in context: A376030 A006567 A263240 * A246045 A359978 A108388

Adjacent sequences: A246040 A246041 A246042 * A246044 A246045 A246046

KEYWORD

nonn,base

AUTHOR

Andreas Boe, Aug 23 2014

STATUS

approved