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A118488
Squares for which the sum of the digits is a triangular number.
1
0, 1, 64, 100, 361, 1225, 2116, 3025, 5041, 6400, 10000, 17956, 18496, 21025, 23104, 26569, 29584, 32041, 36100, 38809, 47089, 54289, 58564, 59536, 63001, 68644, 69696, 77284, 82369, 87616, 88804, 94249, 110224, 117649, 122500, 128881, 130321
OFFSET
1,3
LINKS
EXAMPLE
26569 = 163^2 is in the sequence because it is a square and the sum of its digits, 2+6+5+6+9 = 28, is a triangular number.
MATHEMATICA
Select[Range[0, 361]^2, IntegerQ @ Sqrt[8 * Plus @@ IntegerDigits[#] + 1] &] (* Amiram Eldar, Mar 24 2021 *)
PROG
(PARI) isok(n) = issquare(n) && ispolygonal(sumdigits(n), 3); \\ Michel Marcus, Feb 27 2014
CROSSREFS
Intersection of A000290 and A187744.
Cf. A000217.
Sequence in context: A255990 A104022 A061099 * A088033 A303960 A304603
KEYWORD
base,nonn
AUTHOR
Luc Stevens (lms022(AT)yahoo.com), May 05 2006
STATUS
approved