This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A346580 #7 Jul 25 2021 02:41:21
%S A346580 1,5,45,440,4750,54081,642341,7861216,98480286,1256564750,16273981757,
%T A346580 213378921432,2826867619108,37782552518473,508840821825750,
%U A346580 6898459208449920,94070535317459017,1289430373107917718,17755914760643605781,245518560759177014000,3407586451859019939012
%N A346580 a(n) = (1/(6*n)) * Sum_{d|n} mu(n/d) * binomial(6*d,d).
%C A346580 Inverse Euler transform of A002295.
%C A346580 Moebius transform of A261499.
%t A346580 Table[(1/(6 n)) Sum[MoebiusMu[n/d] Binomial[6 d, d], {d, Divisors[n]}], {n, 21}]
%o A346580 (PARI) a(n) = sumdiv(n, d, moebius(n/d)*binomial(6*d,d))/(6*n); \\ _Michel Marcus_, Jul 24 2021
%Y A346580 Cf. A002295, A004355, A008683, A022553, A261499, A346577, A346578, A346579, A346581, A346582.
%K A346580 nonn
%O A346580 1,2
%A A346580 _Ilya Gutkovskiy_, Jul 24 2021