cp's OEIS Frontend

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.

A220416 Table T(n,k) = ((n+k-1)*(n+k-2)/2+n)^n, n,k >0 read by antidiagonals.

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%I A220416 #38 Feb 16 2022 18:24:51
%S A220416 1,2,9,4,25,216,7,64,729,10000,11,144,2197,38416,759375,16,289,5832,
%T A220416 130321,3200000,85766121,22,529,13824,390625,11881376,387420489,
%U A220416 13492928512,29,900,29791,1048576,39135393,1544804416,64339296875,2821109907456
%N A220416 Table T(n,k) = ((n+k-1)*(n+k-2)/2+n)^n, n,k >0 read by antidiagonals.
%C A220416 The first column is A000124.
%H A220416 Boris Putievskiy, <a href="/A220416/b220416.txt">Rows n = 1..30 of triangle, flattened</a>
%H A220416 Boris Putievskiy, <a href="http://arxiv.org/abs/1212.2732">Transformations Integer Sequences And Pairing Functions</a>, arXiv:1212.2732 [math.CO], 2012.
%F A220416 As a linear array, the sequence is a(n) = n^A002260(n) or
%F A220416 a(n) = n^(n-t(t+1)/2), where t=floor[(-1+sqrt(8*n-7))/2].
%e A220416 The start of the sequence as triangle array is:
%e A220416   1;
%e A220416   2,9;
%e A220416   4,25,216;
%e A220416   7,64,729,10000;
%e A220416   11, 144, 2197, 38416, 759375;
%e A220416   ...
%o A220416 (Python)
%o A220416 t=int((math.sqrt(8*n-7) - 1)/ 2)
%o A220416 m=n**(n-t*(t+1)/2)
%Y A220416 Cf. A002260, A000124.
%K A220416 nonn,tabl
%O A220416 1,2
%A A220416 _Boris Putievskiy_, Dec 14 2012