A165550 - OEIS

%I #8 Aug 16 2017 17:10:37

%S 0,1,2,3,10,20,30,33,100,200,300,330,333,1000,1143,1431,2000,2242,

%T 3000,3233,3300,3330,3331,3333,3411,3433,4131,10000,11234,11243,11344,

%U 11403,11430,11432,11433,12235,12523,13134,13142,13144,13241,13431,13522

%N Sum of digits of square is sum of square of digits.

%H Rémy Sigrist, <a href="/A165550/b165550.txt">Table of n, a(n) for n = 1..10000</a>

%e Consider n=33: n^2 is 1089, sum of square of digits is 3^2+3^2=18, and sum of digits of square is 1+0+8+9=18, thus 33 appears in the sequence.

%o (PARI) digsum(n) = my(s=0); while(n,s=s+n%10;n=n\10); s;

%o sqadigsum(n) = my(s=0); while(n,s=s+(n%10)^2;n=n\10); s;

%o for(n=0,100000, if(sqadigsum(n)==digsum(n^2), print1(n, ",") ) )

%K base,easy,nonn

%O 1,3

%A _Rémy Sigrist_, Sep 21 2009

%E Offset fixed by _Rémy Sigrist_, Feb 03 2017