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A341067 Number of ways to write n as an ordered sum of 7 squarefree numbers. 8
1, 7, 28, 77, 168, 315, 553, 932, 1505, 2282, 3297, 4634, 6447, 8771, 11607, 15029, 19390, 24885, 31500, 39137, 48335, 59584, 73003, 88109, 105525, 126112, 150472, 177632, 208160, 243194, 284102, 329357, 379379, 435477, 500108, 571124, 648998, 735112, 833483, 940765, 1057679 (list; graph; refs; listen; history; text; internal format)
OFFSET
7,2
LINKS
FORMULA
G.f.: (Sum_{k>=1} mu(k)^2 * x^k)^7.
MAPLE
b:= proc(n, t) option remember;
`if`(n=0, `if`(t=0, 1, 0), `if`(t<1, 0, add(
`if`(numtheory[issqrfree](j), b(n-j, t-1), 0), j=1..n)))
end:
a:= n-> b(n, 7):
seq(a(n), n=7..47); # Alois P. Heinz, Feb 04 2021
MATHEMATICA
nmax = 47; CoefficientList[Series[Sum[MoebiusMu[k]^2 x^k, {k, 1, nmax}]^7, {x, 0, nmax}], x] // Drop[#, 7] &
CROSSREFS
Sequence in context: A073995 A357694 A341986 * A061968 A223772 A024012
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Feb 04 2021
STATUS
approved

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Last modified March 29 06:57 EDT 2024. Contains 371265 sequences. (Running on oeis4.)