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A003964 Fully multiplicative with a(prime(k)) = partition(k+1). 5
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 14, 15, 16, 22, 18, 30, 20, 21, 22, 42, 24, 25, 30, 27, 28, 56, 30, 77, 32, 33, 44, 35, 36, 101, 60, 45, 40, 135, 42, 176, 44, 45, 84, 231, 48, 49, 50, 66, 60, 297, 54, 55, 56, 90, 112, 385, 60, 490, 154, 63, 64, 75, 66, 627, 88, 126, 70 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

If n = Product p(k)^e(k) then a(n) = Product partition(k+1)^e(k).

Multiplicative with a(p^e) = A000041(A000720(p)+1)^e. - David W. Wilson, Aug 01 2001

MAPLE

with(numtheory): with(combinat):

a:= n-> mul(numbpart(pi(i[1])+1)^i[2], i=ifactors(n)[2]):

seq(a(n), n=1..82);  # Alois P. Heinz, Jan 14 2021

MATHEMATICA

f[p_, e_] := PartitionsP[PrimePi[p] + 1]^e; a[n_] := Times @@ (f @@@ FactorInteger[n]); Array[a, 100] (* Amiram Eldar, Aug 29 2019 *)

PROG

(PARI) a(n) = my(f=factor(n)); for (k=1, #f~, f[k, 1] = numbpart(primepi(f[k, 1])+1)); factorback(f); \\ Michel Marcus, Jan 14 2021

CROSSREFS

Cf. A000041, A000720, A299200.

Sequence in context: A297280 A048324 A048337 * A023781 A135578 A050607

Adjacent sequences:  A003961 A003962 A003963 * A003965 A003966 A003967

KEYWORD

nonn,look,mult

AUTHOR

Marc LeBrun, N. J. A. Sloane.

EXTENSIONS

Description corrected and sequence extended by David W. Wilson.

STATUS

approved

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Last modified June 22 14:32 EDT 2021. Contains 345380 sequences. (Running on oeis4.)