A072806 Primes of the form 6k+5 written in base 5.

10, 21, 32, 43, 104, 131, 142, 203, 214, 241, 313, 324, 401, 412, 423, 1011, 1022, 1044, 1132, 1143, 1204, 1231, 1242, 1402, 1413, 1424, 2001, 2012, 2023, 2034, 2111, 2133, 2221, 2232, 2342, 2403, 2414, 3013, 3024, 3101, 3134, 3211, 3233, 3244, 3321

Offset: 1

Author

Labos Elemer, Jul 12 2002

Keywords

• base
• nonn

Examples

			41 = 25 + 3*5 + 1 = 131_5.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A007091, A007528.

Cf. A008713, A072803, A072804, A072805, A072807.

Programs

Mathematica

Do[s=Prime[n]; If[Mod[s, 6]==5, Print[BaseForm[s, 5]]], {n, 1, 256}]
FromDigits[IntegerDigits[#, 5]] & /@  Select[Table[6 n + 5, {n, 0, 100}], PrimeQ] (* Harvey P. Dale, Oct 05 2023 *)

PARI

lista(nn) = for (n=0, nn, if (isprime(p=6*n+5), print1(fromdigits(digits(p, 5)), ", "))); \\ Michel Marcus, Jul 09 2018

Formula

a(n) = A007091(A007528(n)). - Michel Marcus, Jul 09 2018