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A169836
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Perfect squares that are a product of two distinct triangular numbers.
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2
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0, 36, 900, 1225, 7056, 32400, 41616, 44100, 88209, 108900, 298116, 705600, 1368900, 1413721, 1498176, 2924100, 5336100, 8643600, 8820900, 9217296, 10432900, 15210000, 24147396, 37088100, 48024900, 50893956, 50979600, 52490025, 55353600, 80568576
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OFFSET
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1,2
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COMMENTS
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a(47) = 1728896400 is the product of two distinct triangular numbers in two different ways. 1728896400 = A000217(8) * A000217(9800) = A000217(27) * A000217(3024). - Donovan Johnson, Sep 01 2012
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LINKS
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Donovan Johnson, Table of n, a(n) for n = 1..1000
Erich Friedman, What's Special About This Number? (See entry 7056.)
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FORMULA
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a(n) = (A175497(n))^2. [From R. J. Mathar, Jun 03 2010]
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EXAMPLE
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Examples: 900=3*300. 7056 = 6*1176. 1368900 = 6*228150. 44100 = 36*1225.
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CROSSREFS
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Cf. A000217, A054731, A169835.
Sequence in context: A145150 A166790 A001812 * A075916 A062150 A011811
Adjacent sequences: A169833 A169834 A169835 * A169837 A169838 A169839
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KEYWORD
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nonn
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AUTHOR
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R. J. Mathar, May 30 2010
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EXTENSIONS
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More terms from R. J. Mathar, Jun 03 2010
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STATUS
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approved
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