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 A105604 #7 Nov 02 2017 09:14:02 %S A105604 1,1,1,1,1,3,1,5,3,11,1,105,1,43,33,85,1,1197,1,1705,129,683,1,23205, %T A105604 11,2731,171,27305,1,2370291,1,21845,2049,43691,473,5679765,1,174763, %U A105604 8193,5941925,1,621456339,1,6990505,622611,2796203,1,1437248085,43,346729141,131073,111848105,1,22861753173,7513,1521134245 %N A105604 Sylvester dividends for Jacobsthal numbers. %C A105604 Divide each Jacobsthal number by its primitive part. %H A105604 Antti Karttunen, <a href="/A105604/b105604.txt">Table of n, a(n) for n = 1..4096</a> %F A105604 a(n) = A001045(n)/A105603(n). %o A105604 (PARI) %o A105604 A001045(n) = ((2^n - ((-1)^n)) / 3); %o A105604 A105603(n) = if(1==n,n,(-1)^eulerphi(n)*polcyclo(n, -2)); \\ After _Wolfdieter Lang_'s formula in that entry. %o A105604 A105604(n) = (A001045(n)/A105603(n)); \\ _Antti Karttunen_, Nov 01 2017 %Y A105604 Cf. A001045, A105603. %K A105604 easy,nonn %O A105604 1,6 %A A105604 _Paul Barry_, Apr 15 2005 %E A105604 More terms from _Antti Karttunen_, Nov 01 2017