A008333 Sum of divisors of p+1, p prime.

4, 7, 12, 15, 28, 24, 39, 42, 60, 72, 63, 60, 96, 84, 124, 120, 168, 96, 126, 195, 114, 186, 224, 234, 171, 216, 210, 280, 216, 240, 255, 336, 288, 336, 372, 300, 240, 294, 480, 360, 546, 336, 508, 294, 468, 465, 378, 504, 560, 432, 546, 744, 399, 728, 528, 720, 720, 558

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..999 (offset adapted by Michel Marcus)

Crossrefs

Cf. A000203, A008864, A051027.

Programs

Maple

for i from 1 to 500 do if isprime(i) then print(sigma(i+1)); fi; od;

Mathematica

lst={};Do[AppendTo[lst, DivisorSigma[1, Prime[n]+1]], {n, 6!}];lst (* Vladimir Joseph Stephan Orlovsky, Sep 20 2008 *)

PARI

a(n) = sigma(prime(n)+1); \\ Michel Marcus, May 11 2016

Formula

a(n) = A000203(A008864(n)). - Michel Marcus, May 11 2016

a(n) = A000203(A000203(prime(n))) = A051027(prime(n)). - Michel Marcus, May 11 2016

Extensions

Offset 1 from Michel Marcus, Apr 19 2020