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 A381228 #12 Feb 28 2025 05:13:29 %S A381228 1,2,3,4,4,3,10,7,7,5,5,12,12,8,8,13,13,21,36,22,22,37,14,4,9,6,6,39, %T A381228 39,24,24,15,15,69,41,41,25,25,42,42,72,72,10,10,43,16,16,74,128,44, %U A381228 44,75,130,76,76,27,27,77,77,134,134,78,46,46,17,17,79,79,28 %N A381228 Smallest k such that n appears in row k of the triangle in A381227, or -1 if n never appears in A381227. %C A381228 Conjecture: Every positive integer appears in A381227. %e A381228 14 first appears in row 8 of A381227, so a(14) = 8. %Y A381228 Cf. A139004, A381226, A381227, A381229. %K A381228 nonn %O A381228 1,2 %A A381228 _N. J. A. Sloane_, Feb 25 2025 %E A381228 More terms from _Jinyuan Wang_, Feb 25 2025