A089377 Numbers whose product of digits +1 and -1 gives twin prime pairs.

4, 6, 14, 16, 22, 23, 26, 29, 32, 34, 36, 41, 43, 56, 61, 62, 63, 65, 67, 76, 89, 92, 98, 114, 116, 122, 123, 126, 129, 132, 134, 136, 141, 143, 156, 161, 162, 163, 165, 167, 176, 189, 192, 198, 212, 213, 216, 219, 221, 223, 231, 232, 233, 235, 237, 249, 253, 256

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

36 is a member since 3*6 = 18 and (17,19) is a twin prime pair.

Mathematica

prodDig[n_] := Times @@ IntegerDigits[n]; Select[Range[256], And @@ PrimeQ [prodDig[#] + {-1, 1}] &] (* Amiram Eldar, Dec 27 2019 *)
Select[Range[300], AllTrue[Times@@IntegerDigits[#]+{1, -1}, PrimeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 26 2021 *)

Crossrefs

Cf. A001097, A001359, A006512, A007954.

Sequence in context: A310619 A343501 A029641 * A310620 A310621 A090773

Adjacent sequences: A089374 A089375 A089376 * A089378 A089379 A089380

Keyword

base,nonn

Author

Amarnath Murthy, Nov 08 2003

Extensions

More terms from David Wasserman, Sep 15 2005

Status

approved