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 A039912 #15 Jul 08 2025 22:40:31 %S A039912 1,1,-2,1,-3,4,1,-4,6,-8,1,-5,10,-9,16,1,-6,15,-20,9,-32,1,-7,21,-35, %T A039912 36,0,64,1,-8,28,-56,70,-64,-27,-128,1,-9,36,-84,126,-125,120,81,256, %U A039912 1,-10,45,-120,210,-252,200,-240,-162,-512,1,-11,55,-165,330,-462,463,-275,496,243,1024,1,-12,66,-220,495,-792,924 %N A039912 Triangle related to number of compositions of n into relatively prime summands. %H A039912 H. W. Gould, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Scanned/2-4/gould.pdf">Binomial coefficients, the bracket function and compositions with relatively prime summands</a>, Fib. Quart. 2 (1964), 2. %e A039912 Triangle begins: %e A039912 1; %e A039912 1, -2; %e A039912 1, -3, 4; %e A039912 1, -4, 6, -8; %e A039912 1, -5, 10, -9, 16; %e A039912 1, -6, 15, -20, 9, -32; %e A039912 1, -7, 21, -35, 36, 0, 64; %e A039912 ... %Y A039912 Cf. A126713. %K A039912 tabl,sign %O A039912 2,3 %A A039912 _N. J. A. Sloane_ %E A039912 More terms from _Vladeta Jovovic_, Feb 26 2008