A031216 Write primes in base 10 but interpret as if in base 11.

2, 3, 5, 7, 12, 14, 18, 20, 25, 31, 34, 40, 45, 47, 51, 58, 64, 67, 73, 78, 80, 86, 91, 97, 106, 122, 124, 128, 130, 135, 150, 155, 161, 163, 174, 177, 183, 190, 194, 201, 207, 210, 221, 223, 227, 229, 254, 267, 271, 273, 278, 284, 287, 298, 304, 311

Offset: 1

Author

Jeff Burch

Keywords

• nonn
• base

Examples

			13_10 = 11+2 -> 12_11, so 5th term is 12.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000040, A171397.

Programs

Maple

a:= n-> (l-> add(l[i]*11^(i-1), i=1..nops(l)))(convert(ithprime(n),base,10)):
seq(a(n), n=1..56);  # Alois P. Heinz, Aug 30 2024

PARI

a(n) = fromdigits(digits(prime(n)), 11); \\ Michel Marcus, Aug 31 2024

Python

from sympy import prime
def A031216(n): return int(str(prime(n)),11) # Chai Wah Wu, Aug 30 2024

Formula

a(n) = A171397(prime(n)). - Michel Marcus, Aug 31 2024

Extensions

a(25) corrected by Sean A. Irvine, Apr 16 2020