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Search: id:A083390
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| A083390 |
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m such that 2m + 1 divides lcm(1,3,5,...,2m - 1). |
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+0
1
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| 7, 10, 16, 17, 19, 22, 25, 27, 28, 31, 32, 34, 37, 38, 42, 43, 45, 46, 47, 49, 52, 55, 57, 58, 59, 61, 64, 66, 67, 70, 71, 72, 73, 76, 77, 79, 80, 82, 85, 87, 88, 91, 92, 93, 94, 97, 100, 101, 102, 103, 104, 106, 107, 108, 109, 110, 112, 115, 117, 118, 122, 123, 124, 126
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Also m for which A025547(m)=A025547(m+1). Query: a(n) seems to be equal to A030343(n+4) - 1. Is this true?
Whilst any odd number>1 can be the leg of a primitive Pythagorean triangle, the m-th odd number 2m+1=A061346 forms leg common to more than one PPT. - Lekraj Beedassy (blekraj(AT)yahoo.com), Jul 12 2006
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FORMULA
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a(n) = (A061346(n)-1)/2. - David Wasserman (wasserma(AT)spawar.navy.mil), Oct 26 2004
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EXAMPLE
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10 is in the sequence because we have 2*10 - 1 = 19 and lcm(1,3,5,...,19)=166966608033225=7950790858725*21 which is divisible by 2*10 + 1 = 21.
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CROSSREFS
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Cf. A080765.
Sequence in context: A020743 A088350 A085382 this_sequence A033817 A098748 A020692
Adjacent sequences: A083387 A083388 A083389 this_sequence A083391 A083392 A083393
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KEYWORD
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nonn
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AUTHOR
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Lekraj Beedassy (blekraj(AT)yahoo.com), Jun 11 2003
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EXTENSIONS
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More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Oct 26 2004
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