A235377 Positions of 10s in A235354.

56, 57, 69, 78, 83, 89, 92, 95, 104, 109, 111, 123, 124, 128, 136, 139, 142, 158, 160, 171, 173, 176, 177, 178, 180, 185, 194, 200, 201, 203, 211, 214, 219, 222, 223, 228, 231, 236, 237, 241, 245, 246, 248, 256, 259, 270, 274, 280, 281, 296, 298, 302, 307, 314

Offset: 1

Author

Vladimir Shevelev and Peter J. C. Moses, Jan 08 2014

Keywords

• nonn
• base

Comments

If prime(a(n)) is written in base k>=2, and the k-representation is read in decimal, then all such numbers, for k = 2,3,...,9, are composite.

Crossrefs

Cf. A052033, A235354, A235376, A236174, A236437.

Programs

PARI

isok(n) = {my(p = prime(n)); for (b = 2, 9, if (isprime(subst(Pol(digits(p, b)), x, 10)), return(0));); return (1);} \\ Michel Marcus, Jan 18 2014