A141138 a(n) = prime(A028815(n) - 1) - 1.

1, 2, 4, 10, 16, 30, 40, 58, 66, 82, 108, 126, 156, 178, 190, 210, 240, 276, 282, 330, 352, 366, 400, 430, 460, 508, 546, 562, 586, 598, 616, 708, 738, 772, 796, 858, 876, 918, 966, 990, 1030, 1062, 1086, 1152, 1170, 1200, 1216, 1296, 1408, 1432, 1446, 1470

Offset: 0

Author

Juri-Stepan Gerasimov, Jul 31 2008

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A028815, A141130, A141132, A141133, A141136.

Programs

Magma

A141138:= func< n | n eq 0 select 1 else NthPrime(NthPrime(n)) -1 >;
[A141138(n): n in [0..50]]; // G. C. Greubel, Aug 05 2024

Mathematica

A141138[n_]:= If[n==0, 1, Prime[Prime[n]] -1];
Table[A141138[n], {n,0,70}] (* G. C. Greubel, Aug 05 2024 *)

SageMath

def A141138(n): return 1 if n==0 else nth_prime(nth_prime(n))-1
[A141138(n) for n in range(71)] # G. C. Greubel, Aug 05 2024

Formula

a(n) = A000040(A000040(n)) - 1, with a(0) = 1. - G. C. Greubel, Aug 05 2024

Extensions

a(14), a(28) corrected by D. S. McNeil, Mar 21 2009

Offset changed by G. C. Greubel, Aug 05 2024