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 A381777 #5 Mar 07 2025 09:05:14 %S A381777 0,0,1,2,3,6,11,22,44,92,193,414,896,1966,4347,9700,21787,49262, %T A381777 111976,255824,586996,765220,1187129,2186146,3966763,7642844,14733649, %U A381777 29037924,57062745,113051998,222948526,438614648,853410655,1637949306,3069032471,5548974602,9438433065 %N A381777 Self-convolution of A001190. %H A381777 David Serena and William J. Buchanan, <a href="https://arxiv.org/abs/2503.02663">Equivalence Classes Induced by Binary Tree Isomorphism -- Generating Functions</a>, arXiv:2503.02663 [math.CO], 2025. See p. 5. %t A381777 terms = 20; A[_] = 0; Do[A[x_] = x + (1/2)*(A[x]^2 + A[x^2]) + O[x]^terms // Normal, terms]; CoefficientList[A[x]^2, x] (* after _Jean-François Alcover_, Jan 10 2018 *) %Y A381777 Cf. A001190. %K A381777 nonn,easy %O A381777 0,4 %A A381777 _Stefano Spezia_, Mar 07 2025