A296097 Triangular numbers that can be represented as a product of two triangular numbers greater than 1, as a product of three triangular numbers greater than 1, and as a product of four triangular numbers greater than 1.

25200, 61425, 145530, 500500, 749700, 828828, 1185030, 2031120, 2162160, 2821500, 4573800, 5364450, 13857480, 17907120, 20991960, 21783300, 24643710, 27162135, 29610360, 30933045, 34283340, 37191000, 40901490, 60769800, 64292130, 71216145, 76576500, 90041490

Offset

1,1

Comments

Triangular numbers in the products need not be distinct, that is, duplicates in the products are allowed.

A subsequence of A188630 and of A295769.

Links

Table of n, a(n) for n=1..28.

Example

25200 = 210 * 120 = 120 * 21 * 10 = 28 * 15 * 10 * 6.

Crossrefs

Cf. A000217, A188630, A295769.

Sequence in context: A252614 A253530 A190319 * A076583 A226501 A046709

Adjacent sequences: A296094 A296095 A296096 * A296098 A296099 A296100

Keyword

nonn

Author

Alex Ratushnyak, Dec 04 2017

Status

approved