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A326895 Number of chiral pairs of color loops of length n with integer entries that cover an initial interval of positive integers. 4

%I #12 Sep 16 2019 04:29:52

%S 0,0,1,6,48,370,3341,33966,393468,5111100,73753685,1170469192,

%T 20263758984,380047816638,7676106093049,166114206920706,

%U 3834434320842720,94042629507775794,2442147034668044933,66942194905680941268,1931543452344523778392,58519191359156026158522

%N Number of chiral pairs of color loops of length n with integer entries that cover an initial interval of positive integers.

%H Andrew Howroyd, <a href="/A326895/b326895.txt">Table of n, a(n) for n = 1..200</a>

%F Inverse Moebius transform of A326888.

%o (PARI) a(n)={sum(k=1, n, -k!*(stirling((n+1)\2,k,2) + stirling(n\2+1,k,2))/4 + k!*sumdiv(n,d, eulerphi(d)*stirling(n/d,k,2))/(2*n))} \\ _Andrew Howroyd_, Sep 13 2019

%Y Row sums of A305541.

%Y Cf. A326888.

%K nonn

%O 1,4

%A _Andrew Howroyd_, Sep 13 2019

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Last modified April 24 12:43 EDT 2024. Contains 371940 sequences. (Running on oeis4.)