OFFSET
1,2
COMMENTS
a(A002145(n))=1.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..10000
FORMULA
G.f.: Sum_{k>=1} x^k*(1 + 2*x^k + 4*x^(3*k) + 3*x^(4*k) + 2*x^(5*k))/(1 - x^(4*k))^2. - Ilya Gutkovskiy, Sep 12 2019
MATHEMATICA
sd[n_]:= Total[Select[Divisors[n], !IntegerQ[(# - 3) / 4]&]]; Array[sd, 100] (* Vincenzo Librandi, May 17 2013 *)
PROG
(PARI) for(n=1, 100, print1(sumdiv(n, d, if(d%4!=3, d))", "))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Ralf Stephan, Apr 02 2003
STATUS
approved