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A341795
Number of ways to write n as an ordered sum of 4 nonzero tetrahedral numbers.
7
1, 0, 0, 4, 0, 0, 6, 0, 0, 8, 0, 0, 13, 0, 0, 12, 0, 0, 10, 4, 0, 12, 12, 0, 6, 12, 0, 4, 16, 0, 4, 24, 0, 0, 16, 0, 1, 24, 6, 0, 24, 12, 0, 16, 6, 0, 28, 12, 0, 12, 12, 0, 12, 12, 0, 16, 30, 4, 12, 12, 4, 16, 24, 0, 16, 24, 4, 24, 6, 0, 12, 24, 12, 12, 18, 12, 13, 36, 0, 0, 24, 12
OFFSET
4,4
FORMULA
G.f.: ( Sum_{k>=1} x^binomial(k+2,3) )^4.
MATHEMATICA
nmax = 85; CoefficientList[Series[Sum[x^Binomial[k + 2, 3], {k, 1, nmax}]^4, {x, 0, nmax}], x] // Drop[#, 4] &
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Feb 19 2021
STATUS
approved