A369577 a(n) = [x^n] Product_{j=1..n, k=1..n} 1/(1 - x^(k^j)).
1, 1, 4, 14, 52, 193, 724, 2736, 10404, 39759, 152555, 587323, 2267578, 8776197, 34038411, 132262696, 514774705, 2006461961, 7830924282, 30599035846, 119692591204, 468651774760, 1836626054421, 7203559635483, 28274941506056, 111060542576799, 436515284729667
Offset: 0
Keywords
Links
- Vaclav Kotesovec, Table of n, a(n) for n = 0..1000
Programs
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Mathematica
Table[SeriesCoefficient[Product[Product[1/(1 - x^(k^j)), {k, 1, n^(1/j)}], {j, 1, n}], {x, 0, n}], {n, 0, 40}]
Formula
a(n) ~ c * 4^n / sqrt(n), where c = 0.52405470637768487694539405770364130415279761385131429278498764796443...