A282569 Number of compositions (ordered partitions) of n into multiplicatively perfect numbers (A007422).
1, 1, 1, 1, 1, 1, 2, 3, 5, 7, 10, 13, 17, 22, 31, 44, 63, 88, 122, 166, 227, 312, 433, 601, 836, 1159, 1604, 2214, 3056, 4220, 5837, 8079, 11188, 15486, 21424, 29624, 40961, 56641, 78344, 108379, 149940, 207427, 286933, 396880, 548943, 759273, 1050234, 1452740, 2009545, 2779745, 3845085, 5318633, 7356839
Offset: 0
Keywords
Examples
a(8) = 5 because we have [8], [6, 1, 1], [1, 6, 1], [1, 1, 6] and [1, 1, 1, 1, 1, 1, 1, 1].
Links
- Eric Weisstein's World of Mathematics, Multiplicative Perfect Number
- Index entries for sequences related to compositions
Programs
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Mathematica
nmax = 52; CoefficientList[Series[1/(1 - Sum[Boole[Sqrt[k]^DivisorSigma[0, k]/k == k] x^k, {k, 1, nmax}]), {x, 0, nmax}], x]
Formula
G.f.: 1/(1 - Sum_{k>=1} x^A007422(k)).