26122
domain: N
Appears in sequences
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (F(2), F(3), ...), t = (primes).at n=22A024597
- Let p = n-th irregular prime, A000928(n). Then a(n) = smallest value of m such that numerator(Bernoulli(2*m)/(2*m)) / numerator(Bernoulli(2*m)/(2*m*(2*m-1))) equals p.at n=33A092291
- G.f.: A(x) = x + x*ITERATE^2(x + x*ITERATE^4(x + x*ITERATE^6(x + x*ITERATE^8(x + ...)))), where ITERATE^n(F(x)) denotes the n-th iteration of F(x), and the nesting of even iterations continue indefinitely.at n=6A205320
- Poincaré series for hyperbolic reflection group with Coxeter diagram o-(5)-o---o-(5)-o.at n=20A265048
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 137", based on the 5-celled von Neumann neighborhood.at n=35A270276
- Expansion of Product_{k>=1} 1/(1 - x^k)^A050985(k).at n=18A301597
- Number of essentially parallel unoriented series-parallel networks with n elements.at n=10A339224