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A320016
a(1) = a(2) = 1; for n > 2, a(n) = A000005(n) * a(A000005(n)), where A000005(n) gives the number of divisors of n.
3
1, 1, 2, 6, 2, 24, 2, 24, 6, 24, 2, 144, 2, 24, 24, 10, 2, 144, 2, 144, 24, 24, 2, 192, 6, 24, 24, 144, 2, 192, 2, 144, 24, 24, 24, 54, 2, 24, 24, 192, 2, 192, 2, 144, 144, 24, 2, 240, 6, 144, 24, 144, 2, 192, 24, 192, 24, 24, 2, 1728, 2, 24, 144, 14, 24, 192, 2, 144, 24, 192, 2, 1728, 2, 24, 144, 144, 24, 192, 2, 240, 10, 24, 2, 1728
OFFSET
1,3
LINKS
FORMULA
a(1) = a(2) = 1; for n > 2, a(n) = A000005(n) * a(A000005(n)), where A000005(n) gives the number of divisors of n.
MATHEMATICA
Nest[Append[#1, #2 #1[[#2]] ] & @@ {#, DivisorSigma[0, Length@ # + 1]} &, {1, 1}, 82] (* Michael De Vlieger, Nov 25 2018 *)
PROG
(PARI) A320016(n) = if(n<=2, 1, numdiv(n)*A320016(numdiv(n)));
(GAP) a:=[1, 1];; for n in [3..100] do a[n]:=Tau(n)*a[Tau(n)]; od; a; # Muniru A Asiru, Nov 24 2018
CROSSREFS
Cf. also A320009, A320118.
Sequence in context: A008556 A254638 A320118 * A096485 A125032 A076743
KEYWORD
nonn
AUTHOR
Antti Karttunen, Nov 24 2018
STATUS
approved