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A023894
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Number of partitions of n into prime power parts (1 excluded).
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46
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1, 0, 1, 1, 2, 2, 3, 4, 6, 7, 9, 12, 15, 19, 23, 29, 37, 44, 54, 66, 80, 96, 115, 138, 165, 196, 231, 275, 322, 380, 443, 520, 607, 705, 819, 950, 1099, 1268, 1461, 1681, 1932, 2214, 2533, 2898, 3305, 3768, 4285, 4872, 5530, 6267, 7094, 8022, 9060
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OFFSET
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0,5
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LINKS
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FORMULA
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G.f.: Prod(p prime, Prod(k >= 1, 1/(1-x^(p^k))))
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EXAMPLE
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The a(0) = 1 through a(9) = 7 partitions:
() . (2) (3) (4) (5) (33) (7) (8) (9)
(22) (32) (42) (43) (44) (54)
(222) (52) (53) (72)
(322) (332) (333)
(422) (432)
(2222) (522)
(3222)
(End)
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MATHEMATICA
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Table[Length[Select[IntegerPartitions[n], And@@PrimePowerQ/@#&]], {n, 0, 30}] (* Gus Wiseman, Jul 28 2022 *)
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PROG
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(PARI) isprimepower(n)= {ispower(n, , &n); isprime(n)}
lista(m) = {x = t + t*O(t^m); gf = prod(k=1, m, if (isprimepower(k), 1/(1-x^k), 1)); for (n=0, m, print1(polcoeff(gf, n, t), ", ")); }
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CROSSREFS
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The multiplicative version (factorizations) is A000688, coprime A354911.
Twice-partitions of this type are counted by A279784, factorizations A295935.
These partitions are ranked by A355743.
A001222 counts prime-power divisors.
A072233 counts partitions by sum and length.
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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