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%I #19 Feb 28 2024 10:48:18
%S 2778889,4695889,5678689,5697769,5938969,6568969,6589489,6848689,
%T 6895876,7974976,7997584,8779369,9878449,9966649,299739969,377796969,
%U 396686889,458687889,467986689,487658889,488984769,496977849,538889796,557998884,559984896,569967876
%N Squares whose arithmetic mean of digits is 7 (i.e., the sum of digits is 7 times the number of digits).
%C Each term's number of digits is in A056991 (Numbers with digital root 1, 4, 7, or 9). For every term k in A056991, this sequence contains at least one k-digit term, with the exception of k=1 and k=4. (See A316480.)
%H Jon E. Schoenfield, <a href="/A316487/b316487.txt">Table of n, a(n) for n = 1..10000</a>
%e 17313^2 = 299739969, a 9-digit number whose digit sum is 2+9+9+7+3+9+9+6+9 = 63 = 7*9, so 299739969 is a term.
%e 43474^2 = 1889988676, a 10-digit number whose digit sum is 1+8+8+9+9+8+8+6+7+6 = 70 = 7*10, so 1889988676 is a term.
%Y Cf. A056991, A069711, A316480.
%Y Intersection of A000290 and A061424. - _Michel Marcus_, Jul 06 2018
%K nonn,base
%O 1,1
%A _Jon E. Schoenfield_, Jul 04 2018
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