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 A354451 #18 Jul 26 2022 14:04:42 %S A354451 1,0,0,0,1,0,0,2,0,0,0,0,1,0,0,0,0,2,0,0,0,0,2,0,1,0,0,0,0,0,0,2,0,0, %T A354451 0,0,0,0,2,0,1,0,0,0,0,2,0,0,0,2,0,0,0,0,0,0,0,0,2,0,1,0,0,0,0,0,0,2, %U A354451 0,0,0,2,0,0,0,0,2,0,0,0,0,0,2,0,1,0,0,0,0,0,0,0,0,2,0,0,0,2,0,0,0,0,0,0,2 %N A354451 Number of middle divisors of 2*n-1. %C A354451 a(n) is the number of middle divisors of the n-th odd number. %C A354451 a(n) is also the width of the terrace at the level 2*n-1 starting from the top in the main diagonal of the stepped pyramid described in A245092. %C A354451 a(n) is also the number of central subparts in the symmetric representation of sigma(2n-1). For more information about the subparts see A279387. %F A354451 a(n) = A067742(2n-1). %F A354451 a(n) = A067742(A005408(n-1)). %t A354451 a[n_] := DivisorSum[2*n - 1, 1 &, n <= #^2 < 4*n - 2 &]; Array[a, 100] (* _Amiram Eldar_, Jun 01 2022 *) %Y A354451 Bisection of A067742. %Y A354451 Cf. A005408, A099774, A237048, A237270, A237271, A237593, A245092, A249351, A279387, A319529, A354452. %K A354451 nonn %O A354451 1,8 %A A354451 _Omar E. Pol_, May 30 2022