%I
%S 1,7,45,55,67,100,433,4950,5050,38212,65068,190576,295075,299035,
%T 310024,336700,343333,394615,414558,433566,448228,450550,467236,
%U 475497,476191,486486,499500,500500,523513,534898,549550,599743,622414,628408,647362
%N "Kaprekar quadruples": digits of X^4 taken D at a time sum to X (where D is number of digits in X.)
%C Referred to as "natural" Kaprekar numbers on Munafo webpage because a(n) and the 4 pieces of a(n)^4 must all have the same number of digits (some of which can be leading zeros). Analogous to A053816 for squares, as opposed to A006886 and A045913 which allow irregular divisions.
%H Robert Gerbicz, <a href="/A171493/b171493.txt">Table of n, a(n) for n = 1..10852</a>
%H R. Munafo, <a href="http://www.mrob.com/pub/math/seqkaprekar.html">Kaprekar Sequences</a>
%e 7^4 = 2401 ; 2+4+0+1 = 7. 67^4 = 20151121 ; 20+15+11+21 = 67. 4950^4 = 600372506250000 ; 0600+3725+0625+0000 = 4950.
%Y Cf. A006886, A006887, A045913, A053816
%K base,nonn
%O 1,2
%A _Robert Munafo_, Dec 10 2009
%E Added term a(1)=1, _Robert Gerbicz_, Jul 28 2011
