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 A252492 #6 Jan 16 2015 09:24:03 %S A252492 16,17,33,34,50,51,84,119,135,153,169,220,255,272,288,374,441,560,594, %T A252492 714,832,935,1088,1155,1224,1274,1700,2057,2430,2499,2600,4913,5831, %U A252492 12375,14399,28560,31212,37179,194480,336140 %N A252492 The largest prime factor of n*(n+1) equals 17. (Related to the abc conjecture.) %C A252492 Equivalently, the prime factors of n and n+1 are not larger than 17, but not all smaller than 17 (in which case n is in A252493). %C A252492 This sequence is complete by a theorem of Stormer, cf. A002071 and sequences A085152, A085153, A252494, A252493. %C A252492 This is row 7 of A145605. It has A145604(7)=40 terms and ends with A002072(7)=336140. %H A252492 <a href="/index/Ab#abc">OEIS Index entries for sequences related to the abc conjecture</a> %t A252492 Select[Range[345678], FactorInteger[ # (# + 1)][[ -1,1]] == 17 &] %o A252492 (PARI) for(n=1,9e6,vecmax(factor(n++)[,1])<18 && vecmax(factor(n*n--)[,1])==17 && print1(n",")) \\ Skips 2 if n+1 is not 17-smooth: Twice as fast as the naïve version. %Y A252492 Cf. A002473, A086247, A252493, A252494, A085153, A085152. %K A252492 nonn,fini,full %O A252492 1,1 %A A252492 _M. F. Hasler_, Jan 16 2015