A061595 Product of digits + 1 is prime, sum of digits + 1 is prime and sum of digits - 1 is prime.

4, 6, 22, 66, 112, 114, 121, 123, 129, 132, 141, 147, 156, 165, 174, 189, 192, 198, 211, 213, 219, 231, 237, 273, 279, 291, 297, 312, 321, 327, 345, 354, 369, 372, 396, 411, 417, 435, 453, 459, 468, 471, 477, 486, 495, 516, 534, 543, 549, 561, 567, 576, 594

Offset: 1

Author

Felice Russo, May 22 2001

Keywords

• nonn
• base

Examples

			For 147 we have (1*4*7) + 1 = 29, (1+4+7) + 1 = 13, (1+4+7) - 1 = 11.
		

Links

• Harry J. Smith, Table of n, a(n) for n = 1..1003

Crossrefs

Subsequence of A167711.

Programs

Maple

a := proc (n) local nn: nn := convert(n, base, 10): if isprime(1+product(nn[j], j = 1 .. nops(nn))) = true and isprime(1+sum(nn[j], j = 1 .. nops(nn))) = true and isprime(-1+sum(nn[j], j = 1 .. nops(nn))) = true then n else end if end proc: seq(a(n), n = 1 .. 615); # Emeric Deutsch, Aug 02 2009

PARI

isok(k)={my(d=digits(k), s=vecsum(d)); isprime(s+1) && isprime(s-1) && isprime(vecprod(d)+1)} \\ Harry J. Smith, Jul 25 2009

Extensions

a(1)=4 and a(2)=6 added by Emeric Deutsch, Aug 02 2009