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Search: id:A099911
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| A099911 |
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Primes of the form (p*(q-1)+(p-1)*q)/2, where p and q are consecutive odd primes. |
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+0
4
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| 11, 29, 131, 641, 1721, 2441, 3539, 10301, 22349, 36671, 70481, 79241, 170957, 175979, 186191, 198461, 212981, 304127, 313031, 324329, 434939, 655289, 777041, 852827, 1031231, 1126781, 1339781, 1511669, 1571237, 1741079, 1875521, 2003591
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Or, primes of the form prime(n)*prime(n+1)- (prime(n)+prime(n+1))/2.
Subsequence of A099909.
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EXAMPLE
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p=A000040(5)=11, q=A000040(5+1)=13: (11*(13-1)+(11-1)*13)/2 = (132+130)/2 = 131 = A000040(32), therefore 131 is a term.
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MATHEMATICA
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f[n_] := Block[{p = Prime[n], q = Prime[n + 1]}, r = (p*(q - 1) + (p - 1)*q)/2; If[ PrimeQ[r], r, 0]]; l = {}; Do[a = f[n]; If[a != 0, AppendTo[l, a]], {n, 300}]; l (from Robert G. Wilson v Nov 02 2004)
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CROSSREFS
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Cf. A098142.
Sequence in context: A106880 A135064 A053703 this_sequence A118638 A088460 A080083
Adjacent sequences: A099908 A099909 A099910 this_sequence A099912 A099913 A099914
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Oct 29 2004
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Nov 02 2004
Edited by njas at the suggestion of Andrew Plewe, May 21 2007
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