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 A339583 #17 Feb 23 2021 12:32:03 %S A339583 3,7,12,15,9,28,12,31,39,42,18,60,21,56,72,63,27,91,30,90,96,42,36, %T A339583 124,39,49,120,120,45,168,48,127,144,63,54,195,57,70,84,186,63,224,66, %U A339583 180,234,84,72,252,75,217,108,210,81,280,84,248,120,105,90,360,93,112,312,255,99,336 %N A339583 Leading term in row 2*n of A237270. %C A339583 The leading term in row 2*n-1 is n. %C A339583 The first column in A237270, [1, 3, 2, 7, 3, 12, 4, 15, 5, 9, 6, 28, 7, 12, 8, 31, 9, 39, 10, 42, 11, ...], without the initial 1, is A237270(A237590(n)+1). By bisecting this we get the present sequence. %C A339583 Bisection of A241838. - _Omar E. Pol_, Feb 23 2021 %H A339583 N. J. A. Sloane, <a href="/A339583/b339583.txt">Table of n, a(n) for n = 1..2495</a> %e A339583 Row 10 of A237270 is [9, 9], so a(5) = 9 (the first of the two 9's, officially). %Y A339583 Cf. A237270, A237271, A237590, A237593, A241838. %K A339583 nonn %O A339583 1,1 %A A339583 _N. J. A. Sloane_, Dec 25 2020