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 A253609 #13 Jan 27 2025 22:52:02
%S A253609 2,4,3,6,5,9,14,19,11,15,29,57,94,40,22,65,171,483,269,124,23,137,549,
%T A253609 2549,1996,1071,187,30,277,1786,13468,14547,12661,1810,273,43,546,
%U A253609 5563,69298,105091,144229,24916,4142,313,51,1109,17088,353423,750571,1624729,335764,74341,5856,505,61
%N A253609 Array read by upwards antidiagonals: A(n, k) = index of prime(k)^n in A098550.
%C A253609 Entry A(n, k), in row n and column k, is the index of the entry in A098550 such that A098550(A(n, k)) = prime(k)^n.
%C A253609 Conjecture: For all natural numbers i, j, k, prime(k)^i precedes prime(k)^(i+1) and prime(k)^j precedes prime(k+1)^j in A098550.
%e A253609 Array begins:
%e A253609 2, 3, 9, 15, 22, 23, 30, 43, ...
%e A253609 4, 5, 11, 40, 124, 187, 273, 313, ...
%e A253609 6, 19, 94, 269, 1071, 1810, 4142, 5856, ...
%e A253609 14, 57, 483, 1996, 12661, 24916, 74341, 116524, ...
%e A253609 29, 171, 2549, 14547, 144229, 335764, 1300310, 2276597, ...
%e A253609 65, 549, 13468, 105091, 1624729, 4458533, 22501985, 43999361, ...
%e A253609 137, 1786, 69298, 750571, 18146462, 58762243, 387122632, 845496081, ...
%Y A253609 Cf. A098550, A251239 (row 1), A251240 (row 2), A251393 (column 1).
%Y A253609 Cf. A251241 = {1} union {this array}.
%K A253609 nonn,tabl
%O A253609 1,1
%A A253609 _L. Edson Jeffery_, Jan 05 2015
%E A253609 More terms from _Jinyuan Wang_, Jan 26 2025