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 A129317 #11 Oct 26 2019 09:57:49 %S A129317 6,9,16,78,126,161,253,497,715,949,981,1046,1054,1261,1331,1379,1405, %T A129317 1431,1509,1521,1611,1751,1863,1891,2171,2492,2681,2822,3095,3101, %U A129317 3249,3401,3592,3611,3653,3809,4186,4192,4385,4453,4501,4599,4907,5121,5146 %N A129317 The second of the pair of consecutive integers k and k+1 such that sopfr(k) divides sopfr(k+1), where sopfr(k) is the sum of the prime factors of k, counting multiplicity. %C A129317 A129316 is the first element of the pair. %C A129317 A generalization of Ruth-Aaron pairs (A006145). %H A129317 Amiram Eldar, <a href="/A129317/b129317.txt">Table of n, a(n) for n = 1..10000</a> %F A129317 sopfr(k+1) mod sopfr(k) = 0. %F A129317 a(n) = A129316(n+1). - _Amiram Eldar_, Oct 26 2019 %e A129317 a(6)=161 since sopfr(160)=sopfr(2^5*5)=10+5=15 and sopfr(161)=sopfr(7*23)=30. %Y A129317 Cf. A001414, A006145, A039752, A129316, A129318, A129319. %K A129317 easy,nonn %O A129317 1,1 %A A129317 _Walter Kehowski_, Apr 09 2007