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 A186220 #8 Sep 08 2022 08:45:55 %S A186220 2,4,6,9,11,14,16,18,21,23,26,28,30,33,35,38,40,42,45,47,50,52,55,57, %T A186220 59,62,64,67,69,71,74,76,79,81,84,86,88,91,93,96,98,100,103,105,108, %U A186220 110,112,115,117,120,122,125,127,129,132,134,137,139,141,144,146,149,151,154,156,158,161,163,166,168,170,173,175,178,180,182,185,187,190,192,195,197,199,202,204,207,209,211,214,216,219,221,224,226,228,231,233,236,238,240 %N A186220 Adjusted joint rank sequence of (g(i)) and (f(j)) with f(i) before g(j) when f(i)=g(j), where f and g are the triangular numbers and squares. Complement of A186219. %C A186220 See A186219. %H A186220 G. C. Greubel, <a href="/A186220/b186220.txt">Table of n, a(n) for n = 1..10000</a> %F A186220 See A186219. %e A186220 First, write %e A186220 1..3...6..10..15...21..28..36..45... (triangular) %e A186220 1....4.. 9......16...25....36....49.. (square) %e A186220 Replace each number by its rank, where ties are settled by ranking the triangular number before the square: %e A186220 a=(1,3,5,7,8,10,12,13,...) = A186219; %e A186220 b=(2,4,6,9,11,14,16,18,...) = A186220. %t A186220 (See A186219.) %t A186220 Table[n + Floor[(-1 + Sqrt[8*n^2 + 3])/2], {n, 1, 100}] (* _G. C. Greubel_, Aug 26 2018 *) %o A186220 (PARI) vector(100, n, n + floor((-1 + sqrt(8*n^2 + 3))/2)) \\ _G. C. Greubel_, Aug 26 2018 %o A186220 (Magma) [n + Floor((-1 + Sqrt(8*n^2 + 3))/2): n in [1..100]]; // _G. C. Greubel_, Aug 26 2018 %Y A186220 Cf. A186219, A186221, A186222. %K A186220 nonn %O A186220 1,1 %A A186220 _Clark Kimberling_, Feb 15 2011