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A271629
Squares that are the sum of the digits of the numbers from 0 to n, for some n.
2
0, 1, 36, 81, 100, 144, 289, 441, 784, 900, 1225, 1296, 3025, 3600, 5041, 5625, 6400, 8100, 8649, 10000, 11881, 15625, 15876, 18225, 23716, 36100, 41616, 44100, 50625, 55225, 57600, 62001, 67600, 72900, 78400, 99225, 122500, 129600, 136900, 145161, 168921, 189225
OFFSET
1,3
LINKS
EXAMPLE
0 = 0^2; 1 = 1^2; 0 + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 = 36 = 6^2.
MAPLE
with(numtheory): P:=proc(q) local a, b, c, k, n; a:=0; for n from 0 to q do b:=0; c:=n;
for k from 1 to ilog10(n)+1 do b:=b+(c mod 10); c:=trunc(c/10); od; a:=a+b;
if a=trunc(sqrt(a))*trunc(sqrt(a)) then print(a); fi; od; end: P(10^6);
MATHEMATICA
Select[Accumulate@ Map[Total@ IntegerDigits@ # &, Range[0, 10^4]], IntegerQ@ Sqrt@ # &] (* Michael De Vlieger, Apr 11 2016 *)
PROG
(PARI) lista(nn) = for (n=0, nn, if (issquare(s=sum(k=1, n, sumdigits(k))), print1(s, ", "))); \\ Michel Marcus, Apr 11 2016
CROSSREFS
Sequence in context: A286430 A279901 A335276 * A171675 A136359 A257649
KEYWORD
nonn,easy,base
AUTHOR
Paolo P. Lava, Apr 11 2016
STATUS
approved