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 A139248 #10 Sep 27 2024 05:44:37 %S A139248 1,1,2,1,2,4,8,1,2,4,8,16,32,1,2,4,8,16,32,64,128,256,512,1024,2048,1, %T A139248 2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768,1,2,4,8, %U A139248 16,32,64,128,256,512,1024,2048,4096,8192,16384,32768,65536,131072,1,2,4,8,16 %N A139248 Triangle read by rows: row n lists the proper divisors of n-th even superperfect number A061652(n). %C A139248 Also, row n list the proper divisors of n-th superperfect number A019279(n), if there are no odd superperfect numbers. %C A139248 Row n has A000043(n) - 1 = A090748(n) terms. %H A139248 Omar E. Pol, <a href="http://www.polprimos.com">Determinacion geometrica de los numeros primos y perfectos</a>. %e A139248 Triangle begins: %e A139248 1 %e A139248 1, 2 %e A139248 1, 2, 4, 8 %e A139248 1, 2, 4, 8, 16, 32 %e A139248 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048 %e A139248 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768 %e A139248 ... %Y A139248 Cf. A000043, A000668, A018254, A018487, A019279, A061652, A090748, A133024, A133025, A133031, A133049, A135652, A135653, A135654, A135655, A139246. %K A139248 nonn,tabf %O A139248 1,3 %A A139248 _Omar E. Pol_, Apr 22 2008