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A369709
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Maximal coefficient of (1 + x)^3 * (1 + x^2)^3 * (1 + x^3)^3 * ... * (1 + x^n)^3.
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4
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1, 3, 12, 62, 332, 1974, 12345, 80006, 531524, 3602358, 24836850, 173607568, 1226700784, 8748861828, 62922343566, 455805857978, 3321800235936, 24338840717799, 179217603427200, 1325490660318216, 9841000101286172, 73319407735938570, 548051770664957631, 4108826483323392880
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OFFSET
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0,2
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LINKS
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MATHEMATICA
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Table[Max[CoefficientList[Product[(1 + x^k)^3, {k, 1, n}], x]], {n, 0, 23}]
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PROG
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(PARI) a(n) = vecmax(Vec(prod(k=1, n, (1+x^k)^3))); \\ Michel Marcus, Jan 30 2024
(Python)
from collections import Counter
c = {0:1}
for k in range(1, n+1):
d = Counter(c)
for j in c:
a = c[j]
d[j+k] += 3*a
d[j+2*k] += 3*a
d[j+3*k] += a
c = d
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CROSSREFS
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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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