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A256000
Numbers whose square can be written as sum of at least 3 consecutive triangular numbers in two ways.
0
286, 826, 2739, 3971, 5698, 9196, 10166, 10697, 22990, 61006, 132795, 416790, 766480, 809380, 2396870, 2904434, 3459006, 3688802, 4518514, 11725659, 13111098, 13998608, 15709122, 22173027, 22365267, 23636272, 23823988, 32186742, 33630662, 33658710, 39502086, 46387924, 59101625, 62381858, 89841192
OFFSET
1,1
COMMENTS
Apparently there is an infinity of such numbers and there are no cases of 3 ways.
EXAMPLE
4518514^2 = T(18801)+..+T(50546) = T(52361)+..+T(64316), where T(n) = A000217(n).
CROSSREFS
Cf. A000217 (triangular numbers), A257274.
Sequence in context: A090089 A204379 A025384 * A253329 A356422 A329392
KEYWORD
nonn
AUTHOR
Zak Seidov, May 06 2015
EXTENSIONS
a(10), a(20)-a(35) from Chai Wah Wu, Jan 21 2016
STATUS
approved