OFFSET
1,1
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
EXAMPLE
MATHEMATICA
DivisorSigma[1, #]&/@(2Prime[Range[60]]+1) (* Harvey P. Dale, Sep 17 2013 *)
PROG
(Haskell)
a072057 = a000203 . a072055 -- Reinhard Zumkeller, Oct 10 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
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jun 11 2002
STATUS
approved