OFFSET
1,32
LINKS
MATHEMATICA
c[1, r_] := c[1, r] = 1; c[n_, r_] := c[n, r] = Module[{d, i}, d = Select[Divisors@ n, 1 < # <= r &]; Sum[c[n/d[[i]], d[[i]]], {i, 1, Length@ d}]]; Array[c[#, #] - DivisorSum[#, 1 &, ! PrimeQ@ # &] &, 105] (* Michael De Vlieger, Jul 12 2017, after Dean Hickerson at A001055 *)
PROG
(PARI)
fcnt(n, m) = {local(s); s=0; if(n == 1, s=1, fordiv(n, d, if((d > 1) && (d <= m), s=s+fcnt(n/d, d)))); s};
A001055(n) = fcnt(n, n); \\ This function from Michael B. Porter, Oct 29 2009
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Nov 09 2009
EXTENSIONS
a(64) and a(80) corrected by R. J. Mathar, May 30 2010
STATUS
approved