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%I #13 May 19 2019 22:11:31
%S 0,1,3,10,17,19,27,30,57,93,100,170,190,219,267,270,300,314,327,359,
%T 387,417,423,424,570,685,693,807,828,891,917,930,963,1000,1207,1223,
%U 1317,1333,1673,1693,1700,1827
%N Numbers k such that k^2 and k^4 have the same sum of digits.
%C Let sod(n) := digital sum of n (A007953); here we have sod(n^2) = sod(n^4).
%C Trivial cases:
%C (I) Powers of 10, as sod((10^k)^2)) = sod(10^k)^4)) = 1
%C (II) If N is a term of sequence, then so is 10 * N.
%D Hans Schubart, Einfuehrung in die klassische und moderne Zahlentheorie, Vieweg, Braunschweig, 1974.
%e sod(3^2) = sod(9) = 9 = sod(81) = sod(3^4), so 3 is a term.
%e sod(17^2) = sod(289) = 19 = sod(83521) = sod(17^4), so 17 is a term.
%t Select[Range[0,2000],Total[IntegerDigits[#^2]]==Total[IntegerDigits[#^4]]&] (* _Harvey P. Dale_, Jan 19 2011 *)
%Y Cf. A000290, A000583, A058369, A176012, A176111, A176465.
%K base,nonn
%O 1,3
%A Ulrich Krug (leuchtfeuer37(AT)gmx.de), Apr 25 2010
%E Edited by _D. S. McNeil_, Nov 21 2010
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