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A109441 Union of triangular numbers, even squares, and one less the odd squares, without duplicates. 1
0, 1, 3, 4, 6, 8, 10, 15, 16, 21, 24, 28, 35, 36, 45, 48, 55, 63, 64, 66, 78, 80, 91, 99, 100, 105, 120, 136, 143, 144, 153, 168, 171, 190, 195, 196, 210, 224, 231, 253, 255, 256, 276, 300, 324, 325, 351, 378, 400, 406, 435, 465, 484, 576, 676, 784, 900 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Numbers of form k(k+1)/2, (2k)^2, or (2k+1)^2-1, k>=0.

LINKS

Table of n, a(n) for n=1..57.

MATHEMATICA

Union[Flatten[Table[{(n + 1)^2 - 1, (2*n + 1)*(2*n + 1 - 1)/2, (2*n)^2, (2*n)*(2*n - 1)/2}, {n, 0, 15}]]]

CROSSREFS

Unique values of union of A000217, A016742, and A033996.

Cf. A120722.

Sequence in context: A260485 A120150 A262892 * A343883 A277319 A176986

Adjacent sequences:  A109438 A109439 A109440 * A109442 A109443 A109444

KEYWORD

nonn

AUTHOR

Roger L. Bagula, Jun 22 2007

EXTENSIONS

Edited by Ralf Stephan, Oct 20 2013

STATUS

approved

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Last modified May 16 22:04 EDT 2021. Contains 343955 sequences. (Running on oeis4.)