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A164773 Numbers n with property that average digit of n^2 is s=7. 10
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
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", "))) \\ Charles R Greathouse IV, Nov 01 2009
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).
Sequence in context: A068744 A280404 A054811 * A321001 A054812 A020392
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Aug 26 2009
STATUS
approved

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Last modified March 28 16:58 EDT 2024. Contains 371254 sequences. (Running on oeis4.)