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A076164 Numbers n such that sum of squares of even digits of n equals sum of squares of odd digits of n. 1

%I #21 May 19 2018 19:22:14

%S 0,11112,11121,11211,11356,11365,11536,11563,11635,11653,12111,13156,

%T 13165,13516,13561,13615,13651,15136,15163,15316,15361,15613,15631,

%U 16135,16153,16315,16351,16513,16531,21111,31156,31165,31516,31561

%N Numbers n such that sum of squares of even digits of n equals sum of squares of odd digits of n.

%C The minimal number of digits in any nonzero term is 5.

%C Numbers such that the sum of even digits equals the sum of odd digits are listed in A036301.

%e 11356 is in the sequence because 1^2 + 1^2 + 3^2 + 5^2 = 6^2.

%t oeQ[n_]:=Module[{idn=IntegerDigits[n]},Total[Select[idn,OddQ]^2]== Total[ Select[ idn, EvenQ]^2]]; Select[Range[0,99999],oeQ] (* _Harvey P. Dale_, Sep 23 2011 *)

%o (PARI) is(n)=!vecsum(apply(d->d^2*(-1)^d,digits(n))) \\ _M. F. Hasler_, May 18 2018

%Y Cf. A303269, A036301 (analog without squares), A071650, A304439, A304440, A124176, A124177.

%K nonn,base

%O 1,2

%A _Zak Seidov_, Nov 01 2002

%E Edited and a(1) = 0 added by _M. F. Hasler_, May 18 2018

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Last modified August 19 17:17 EDT 2024. Contains 375310 sequences. (Running on oeis4.)