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 A048947 #21 Feb 16 2025 08:32:40 %S A048947 0,2,3,5,5,7,7,8,9,10,10,12,12,13,14,15,15,16,17,17,18,18,19,19,20,20, %T A048947 20,21,21,22,22,22,22,23,23,24,24,24,24,25,25,25,26,26,26,27,27,27,27, %U A048947 28,28,29,29,29,29,30,30,31,31,31,31,32,32,32,33,33,33,34,34,34,34,35 %N A048947 Let b(n) be the terms of A046528. Then sigma(b(n))=2^(a(n)), where sigma=A000203 is the sum of divisors function. %H A048947 David A. Corneth, <a href="/A048947/b048947.txt">Table of n, a(n) for n = 1..13133</a> %H A048947 David A. Corneth, <a href="/A048947/a048947.gp.txt">PARI program</a> %H A048947 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/DivisorFunction.html">Divisor Function.</a> %o A048947 (PARI) See Corneth link \\ _David A. Corneth_, Oct 21 2019 %Y A048947 Cf. A046528. %K A048947 nonn %O A048947 1,2 %A A048947 _Eric W. Weisstein_ %E A048947 Definition edited by _Daniel Forgues_, Nov 07 2009 %E A048947 Offset changed to 1 by _R. J. Mathar_, Sep 22 2016