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 A137154 #15 Jan 23 2021 23:38:44 %S A137154 1,2,4,9,24,79,331,1803,12954,123983,1592513,27604172,648528166, %T A137154 20722205191,903019659239,53792176322629,4388683843024734, %U A137154 491232972054490915,75545748143323475653,15984344095578889888206 %N A137154 a(n) = Sum_{k=0..n} binomial(2^k + n-k-1, n-k); equals the row sums of triangle A137153. %C A137154 Matrix inverse of A137153 is A137156. %F A137154 G.f.: Sum_{n>=0} x^n/(1-x)^(2^n). - _Paul D. Hanna_, Sep 15 2009 %F A137154 G.f.: Sum_{n>=0} ( (-log(1 - x))^n / n! ) / (1 - 2^n*x). - _Paul D. Hanna_, Jan 23 2021 %t A137154 Table[Sum[Binomial[2^(n-k) + k - 1, k], {k, 0, n}], {n, 0, 20}] (* _Vaclav Kotesovec_, Jan 23 2021 *) %o A137154 (PARI) a(n)=sum(k=0,n,binomial(2^k+n-k-1,n-k)) %o A137154 (PARI) {a(n)=local(A=sum(k=0,n,x^k/(1-x+x*O(x^n))^(2^k)));polcoeff(A,n)} \\ _Paul D. Hanna_, Sep 15 2009 %Y A137154 Cf. A137153, A137155, A137156. %K A137154 nonn %O A137154 0,2 %A A137154 _Paul D. Hanna_, Jan 24 2008