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A175396 Numbers whose sum of squares of digits is a square. 7
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 34, 40, 43, 50, 60, 68, 70, 80, 86, 90, 100, 122, 148, 184, 200, 212, 221, 236, 244, 263, 269, 296, 300, 304, 326, 340, 362, 366, 400, 403, 418, 424, 430, 442, 447, 474, 481, 488, 500, 600, 608, 623, 629, 632, 636, 663 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
Previous name: Numbers n such that Sum_{i=1..r, x(i)^2} is a perfect square, where x(i) = digits of n. r=1+floor(log_10 n).
LINKS
Christian N. K. Anderson, Table of n, a(n) for n = 1..10000
EXAMPLE
34 is a term: 3^2 + 4^2 = 25 = 5^2.
122 is a term: 1^2 + 2^2 + 2^2 = 9 = 3^2.
MATHEMATICA
Select[Range[0, 666], IntegerQ[Sqrt[Plus @@ (IntegerDigits[#]^2)]] &] (* Ivan Neretin, Aug 03 2015 *)
PROG
(PARI) isok(n) = {digs = Vec(Str(n)); issquare(sum(i=1, #digs, eval(digs[i])^2))} \\ Michel Marcus, Jun 02 2013
CROSSREFS
Cf. A084561.
Sequence in context: A108652 A140665 A069024 * A338829 A107085 A212499
KEYWORD
base,easy,nonn
AUTHOR
Ctibor O. Zizka, Apr 30 2010
EXTENSIONS
Corrected and extended by Neven Juric, Jul 12 2010
Simpler definition by Michel Marcus, Jun 02 2013
STATUS
approved

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Last modified March 19 04:58 EDT 2024. Contains 370952 sequences. (Running on oeis4.)