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A366742
The number of divisors of the least coreful infinitary divisor of n.
3
1, 2, 2, 3, 2, 4, 2, 2, 3, 4, 2, 6, 2, 4, 4, 5, 2, 6, 2, 6, 4, 4, 2, 4, 3, 4, 2, 6, 2, 8, 2, 2, 4, 4, 4, 9, 2, 4, 4, 4, 2, 8, 2, 6, 6, 4, 2, 10, 3, 6, 4, 6, 2, 4, 4, 4, 4, 4, 2, 12, 2, 4, 6, 3, 4, 8, 2, 6, 4, 8, 2, 6, 2, 4, 6, 6, 4, 8, 2, 10, 5, 4, 2, 12, 4, 4
OFFSET
1,2
COMMENTS
The sum of divisors of the least coreful infinitary divisor of n is A366744(n).
LINKS
FORMULA
a(n) = A000005(A365296(n)).
a(n) = A000005(n) if and only if n is in A138302.
Multiplicative with a(p^e) = A006519(e) + 1.
MATHEMATICA
f[p_, e_] := 2^IntegerExponent[e, 2] + 1; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100]
PROG
(PARI) a(n) = vecprod(apply(x -> 2^valuation(x, 2) + 1, factor(n)[, 2]));
CROSSREFS
KEYWORD
nonn,easy,mult
AUTHOR
Amiram Eldar, Oct 19 2023
STATUS
approved