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 A145873 #3 Mar 30 2012 17:27:56 %S A145873 280182,822557039,24306922095,4563230639355,15069267560119, %T A145873 112076323050317,50928660480181,3138611770750343,9110883894036198, %U A145873 50251663587824641,76004727767164666,310872228812491206,521749964271465 %N A145873 Smallest k such that k^2+1 is divisible by A002144(n)^9. %e A145873 a(1) = 280182 since A002144(1) = 5, 280182^2+1 = 78501953125 = 5^9*40193 and for no k < 280182 does 5^9 divide k^2+1. a(3) = 24306922095 since A002144(3) = 17, 24306922095^2+1 = 590826461732399189026 = 2*17^9*29*673*127637 and for no k < 24306922095 does 17^9 divide k^2+1. %Y A145873 Cf. A002144 (primes of form 4n+1), A002313 (-1 is a square mod p), A059321, A145296, A145297, A145298, A145299, A145871, A145872. %K A145873 nonn %O A145873 1,1 %A A145873 _Klaus Brockhaus_, Oct 30 2008