A327874 Number of length n primitive (aperiodic) palindromes with integer entries that cover an initial interval of positive integers.
1, 1, 0, 2, 2, 12, 10, 74, 72, 538, 528, 4682, 4668, 47292, 47218, 545820, 545760, 7087260, 7086710, 102247562, 102247020, 1622632496, 1622627890, 28091567594, 28091562840, 526858348368, 526858301088, 10641342969902, 10641342923148, 230283190977852, 230283190431480
Offset: 0
Keywords
Links
- Andrew Howroyd, Table of n, a(n) for n = 0..200
Programs
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PARI
a(n) = {if(n<1, n==0, sumdiv(n, d, moebius(n/d)*sum(k=1, ceil(d/2), k!*stirling(ceil(d/2), k, 2))))}
Formula
a(n) = Sum_{d|n} mu(n/d)*A000670(ceiling(d/2)) for n > 0.