A072057 Sum of divisors of 2*prime(n)+1.

6, 8, 12, 24, 24, 40, 48, 56, 48, 60, 104, 124, 84, 120, 120, 108, 144, 168, 240, 168, 228, 216, 168, 180, 336, 240, 312, 264, 296, 228, 432, 264, 372, 416, 336, 408, 624, 440, 408, 348, 360, 532, 384, 572, 480, 640, 624, 600, 672, 720, 468

Offset: 1

Author

Reinhard Zumkeller, Jun 11 2002

Keywords

• nonn

Examples

			Divisors of A072055(8) = 2*A000040(8)+1 = 2*19+1 = 39: {1,3,13,39}, therefore a(8) = 1+3+13+39 = 56.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000040, A000203, A072055, A072056.

Programs

Haskell

a072057 = a000203 . a072055  -- Reinhard Zumkeller, Oct 10 2013

Mathematica

DivisorSigma[1,#]&/@(2Prime[Range[60]]+1) (* Harvey P. Dale, Sep 17 2013 *)

PARI

a(n) = sigma(2*prime(n)+1); \\ Amiram Eldar, Apr 26 2024

PARI

lista(pmax) = forprime(p = 2, pmax, print1(sigma(2*p+1), ", ")); \\ Amiram Eldar, Apr 26 2024

Formula

a(n) = A000203(A072055(n)).