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 A048537 #26 Feb 16 2025 08:32:40 %S A048537 6,66,215,681,6681,12018,201115,1531159,6541784,21058215,156340764, %T A048537 675098840,5868938806,6666461193,120186956049,586862372693, %U A048537 1115546688777,4176295540840,66589372231193,66634408865198,210842150539318,2108185118566309,21011769217380159,185591342591574215,67412496945629038 %N A048537 a(n) is the smallest value of m such that A002378(m), the m-th oblong number, contains exactly n 4's. %H A048537 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PronicNumber.html">Pronic Number</a> %e A048537 From _Jesse Sealand_, Oct 06 2019: (Start) %e A048537 a(1) = 6 since A002378(6) = 42; %e A048537 a(2) = 66 since A002378(66) = 4422; %e A048537 a(3) = 215 since A002378(215) = 46440; %e A048537 a(4) = 681 since A002378(681) = 464442, etc. %e A048537 (End). %Y A048537 Cf. A048538, A002378. %Y A048537 Cf. A048529, A048531, A048533, A048535, A048539, A048541, A048543, A048545, A048547. %K A048537 nonn,base %O A048537 1,1 %A A048537 _Patrick De Geest_, May 15 1999 %E A048537 a(13)-a(16) from _Lars Blomberg_, Jun 10 2011 %E A048537 Name edited by _Jesse Sealand_, Oct 06 2019 %E A048537 a(17) from _Giovanni Resta_, Oct 09 2019 %E A048537 a(18)-a(25) from _Max Alekseyev_, Jul 25 2024