OFFSET
1,4
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
FORMULA
a(2^n) = n*a(2-1) = n.
EXAMPLE
a(2) = a(2-1) = 1; a(3) = a(3-1) = 1.
MAPLE
a:= proc(n) option remember; `if`(n=1, 1,
mul(i[2]*a(i[1]-1), i=ifactors(n)[2]))
end:
seq(a(n), n=1..100); # Alois P. Heinz, Apr 04 2021
MATHEMATICA
a[1] = 1; a[p_, s_]:= a[p, s]=s a[p-1];
a[n_]:=a[n]= Module[{aux = FactorInteger[n]}, Product[a[aux[[i, 1]], aux[[i, 2]]], {i, Length[aux]}]]; Table[a[n], {n, 100}]
PROG
(PARI) a(n) = my(f=factor(n)); for (k=1, #f~, f[k, 1] = f[k, 2]*a(f[k, 1]-1); f[k, 2] = 1); factorback(f); \\ Michel Marcus, Apr 23 2021
CROSSREFS
KEYWORD
nonn,mult
AUTHOR
José María Grau Ribas, Apr 04 2021
STATUS
approved