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A099502
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Numbers n such that A099501(n) = 3.
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2
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3, 13, 20, 78, 85, 92, 99, 109, 136, 139, 143, 146, 150, 358, 402, 440, 457, 477, 501, 546, 549, 583, 611, 638, 655, 665, 696, 730, 754, 778, 812, 887, 904, 966, 979, 996, 1034, 1051, 2089, 2161, 2427, 2458, 2499, 2697, 2751, 2813, 2840, 2912, 2922, 2929
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OFFSET
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1,1
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COMMENTS
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Granville and Selfridge discuss the numbers n+1 in their paper. For each of these n<10000, Scott Contini found three integers between n^2 and (n+1)^2 such that their product is twice a square. There are 123 instances of n < 10000; 215 instances for n < 20000.
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LINKS
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Donovan Johnson, Table of n, a(n) for n = 1..367
Andrew Granville and John Selfridge, Product of integers in an interval, modulo squares (pdf), Electronic Journal of Combinatorics, Volume 8(1), 2001.
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EXAMPLE
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13 is here because {171,180,190} is the smallest set of integers in the interval [170,195] whose product is twice a square.
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CROSSREFS
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Cf. A099500 (number of subsets), A099501 (size of the subset having the least number of integers).
Sequence in context: A178712 A215567 A214519 * A145024 A055059 A050903
Adjacent sequences: A099499 A099500 A099501 * A099503 A099504 A099505
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KEYWORD
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hard,nonn
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AUTHOR
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T. D. Noe, Oct 20 2004
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STATUS
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approved
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