A367551 a(n) = Sum_{d|n} (d^2+1)^n.
2, 29, 1008, 84162, 11881408, 2566742098, 781250000128, 318651789038947, 167619551409708544, 110462353708225871026, 89116503268220597579776, 86380568889558343409300388, 99045780329059370000000008192
Offset: 1
Keywords
Programs
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PARI
a(n) = sumdiv(n, d, (d^2+1)^n);
Formula
a(n) = Sum_{k=0..n} binomial(n,k) * sigma_{2*k}(n).