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Search: id:A163506
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| A163506 |
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n-th odd nonprime * n-th odd number. |
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+0
1
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| 1, 27, 75, 147, 225, 297, 429, 525, 663, 855, 1029, 1173, 1375, 1539, 1827, 2015, 2277, 2625, 2849, 3159, 3485, 3741, 4095, 4371, 4655, 5049, 5565, 6105, 6555, 6903, 7259, 7623, 7995, 8375, 8901, 9443, 9855, 10575, 11011, 11455, 11907, 12699, 13175, 13833
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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a(n)=A014076(n)*A005408(n-1)
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EXAMPLE
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a(1)=1*1=1; a(2)=9*3=27; a(3)=15*5=75; a(4)=21*7=147; a(5)=25*9=225.
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MAPLE
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A014076 := proc(n) option remember; local a; if n = 1 then 1; else for a from procname(n-1)+2 by 2 do if not isprime(a) then return a; end if; end do: end if; end proc:
A163506 := proc(n) A014076(n) *(2*n-1); end: seq(A163506(n), n=1..80) ; # R. J. Mathar, Oct 10 2009
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CROSSREFS
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Cf. A005408, A014076.
Sequence in context: A043237 A044017 A147651 this_sequence A044165 A044546 A121737
Adjacent sequences: A163503 A163504 A163505 this_sequence A163507 A163508 A163509
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KEYWORD
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nonn
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AUTHOR
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Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Jul 29 2009
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EXTENSIONS
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Formula index corrected, 7279 replaced by 7259 - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 10 2009
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