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A220556 Square array T(n,k) = ((n+k-1)*(n+k-2)/2+n)^k, n,k > 0 read by antidiagonals. 1

%I #31 Feb 16 2022 09:42:21

%S 1,4,3,64,25,6,2401,512,81,10,161051,20736,2197,196,15,16777216,

%T 1419857,104976,6859,400,21,2494357888,148035889,7962624,390625,17576,

%U 729,28,500246412961,21870000000,887503681,33554432,1185921,39304,1225,36

%N Square array T(n,k) = ((n+k-1)*(n+k-2)/2+n)^k, n,k > 0 read by antidiagonals.

%C Column number k of the table T(n,k) is formula for Cantor antidiagonal order in power k

%H Boris Putievskiy, <a href="/A220556/b220556.txt">Table of n, Rows n = 1 to 30 of triangle, flattened</a>

%H Boris Putievskiy, <a href="http://arxiv.org/abs/1212.2732">Transformations Integer Sequences And Pairing Functions</a>, arXiv:1212.2732 [math.CO], 2012.

%F As a linear array, the sequence is a(n) = n^A004763 or a(n) = n^((t*t+3*t+4)/2 - n), where t=floor((-1+sqrt(8*n-7))/2).

%e Square array T(n,k) begins:

%e 1, 4, 64, 2401, 161051, ...

%e 3, 25, 512, 20736, 1419857, ...

%e 6, 81, 2197, 104976, 7962624, ...

%e 10, 196, 6859, 390625, 33554432, ...

%e 15, 400, 17576, 1185921, 115856201, ...

%e 21, 729, 39304, 3111696, 345025251, ...

%e ...

%e The start of the sequence as triangle array is:

%e 1;

%e 4, 3;

%e 64, 25, 6;

%e 2401, 512, 91, 10;

%e 161051, 20736, 2197, 196, 15;

%e ...

%o (Python)

%o t=int((math.sqrt(8*n-7) - 1)/ 2)

%o m=n**((t*t+3*t+4)/2-n)

%Y Column k=1 gives: A000217.

%Y Cf. A004736.

%K nonn,tabl

%O 1,2

%A _Boris Putievskiy_, Dec 16 2012

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