A164773 Numbers n with property that average digit of n^2 is s=7.

1667, 2167, 2383, 2387, 2437, 2563, 2567, 2617, 2626, 2824, 2828, 2963, 3143, 3157, 17313, 19437, 19917, 21417, 21633, 22083, 22113, 22293, 23214, 23622, 23664, 23874, 23937, 24207, 24228, 24267, 24417, 24474, 25824, 25836, 25863, 26067

Offset: 1

Author

Zak Seidov, Aug 26 2009

Keywords

• nonn
• base

Examples

			1667^2=2778889 and (2+7+7+8+8+8+9)/7=7
17313^2=299739969 and (2+9+9+7+3+9+9+6+9)/9=7.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..925

Crossrefs

Subsequence of A164817.

Average of digits of n^2 = s: A164771 (s=1), A164770 (s=2), A164782 (s=3), A164776 (s=4), A164774 (s=5), A164778 (s=6), A164773 (s=7), A164772 (s=8).

Programs

Mathematica

Select[Range[30000],Mean[IntegerDigits[#^2]]==7&] (* Harvey P. Dale, Feb 22 2013 *)

PARI

dsum(n)={my(s=0);while(n>9,s+=n%10;n\=10);s+n};
for(n=1,1e6,if(dsum(n^2)/#Str(n^2)==7,print1(n","))) \\ Charles R Greathouse IV, Nov 01 2009