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 A381231 #43 Mar 14 2025 02:33:30 %S A381231 6,3,4,5,48,15642,14,87,924,23,1074,1066,14524,7051,15000,71709,57604, %T A381231 57554,2056626,2036049,16068,86,934,37142,57439,72635,57342,1394559, %U A381231 358329,2112076,16941,2015018,57124,27572,1837444,29,2058540,54694,2075246,359870,76579,7844,61424,55065,61434,2016279,71877,2271483,305269,57405,1842679 %N A381231 Index of first occurrence of -n in A000319, or -1 if -n never appears there. %C A381231 If a(54) is not -1, then a(54) > 14333074. - _Tim Peters_, Mar 13 2025 %H A381231 Tim Peters, <a href="/A381231/b381231.txt">Table of n, a(n) for n = 0..53</a> %Y A381231 Cf. A000319, A381230. %K A381231 nonn %O A381231 0,1 %A A381231 _N. J. A. Sloane_, Feb 28 2025 %E A381231 a(5)-a(17) from _Hugo Pfoertner_, Feb 28 2025 %E A381231 a(18)-a(50) from _Tim Peters_, Mar 01 2025