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 A380952 #4 Mar 07 2025 06:41:07 %S A380952 0,1,9,29,325,843,4165,9949,185517,424415,1913615,4263339,37624977, %T A380952 82338487,357893805,773201629,26589395581,56890356903,242472512971, %U A380952 514886606335,4359509125419,9201491830421,38741978206771,81367413504171,1364185459323625,2853307081197859 %N A380952 a(n) = 2^(2*n - HammingWeight(n)) * [x^n] ((x - 1)^(-2) - (1 - x)^(-3/2)). %p A380952 gf := (x - 1)^(-2) - (1 - x)^(-3/2): ser := series(gf, x, 32): %p A380952 seq(2^(2*n - add(convert(n, base, 2))) * coeff(ser, x, n), n = 0..25); %Y A380952 Cf. A046161, A000120, A098597, A001790, A173384, A380951. %K A380952 nonn %O A380952 0,3 %A A380952 _Peter Luschny_, Mar 06 2025