

A164773


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


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
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OFFSET

1,1


LINKS

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


EXAMPLE

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.


MATHEMATICA

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


PROG

(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", ")))


CROSSREFS

A164770 (s=2), A164771 (s=1), A164772 (s=8).
Sequence in context: A068744 A280404 A054811 * A321001 A054812 A020392
Adjacent sequences: A164770 A164771 A164772 * A164774 A164775 A164776


KEYWORD

nonn,base,easy


AUTHOR

Zak Seidov, Aug 26 2009


EXTENSIONS

Program by Charles R Greathouse IV, Nov 01 2009


STATUS

approved



