OFFSET
1,12
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65537
EXAMPLE
n=30 with divisor set {1,2,3,5,6,10,15,30}: a(30)=4, as 1<2 & 3=1+2, 1<5 & 6=1+5, 2<3 & 5=2+3 and 5<10 & 15=5+10.
MATHEMATICA
Table[Count[Subsets[#, {2}], _?(Mod[n, Total@ #] == 0 &)] &@ Divisors@ n, {n, 102}] (* Michael De Vlieger, Sep 10 2018 *)
PROG
(PARI) A094518(n) = if(1==n, 0, my(d=divisors(n), c=0); for(i=1, (#d-1), for(j=(i+1), #d, if(!(n%(d[i]+d[j])), c++))); (c)); \\ Antti Karttunen, Sep 10 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, May 06 2004
STATUS
approved