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 A099911 Primes of the form (p*(q-1) + (p-1)*q)/2, where p and q are consecutive odd primes. 3
 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; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Or, primes of the form prime(n)*prime(n+1)- (prime(n)+prime(n+1))/2. Subsequence of A099909. LINKS Table of n, a(n) for n=1..32. EXAMPLE 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. MATHEMATICA 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 (* Robert G. Wilson v, Nov 02 2004 *) Select[((#[[1]](#[[2]]-1))+((#[[1]]-1)#[[2]]))/2&/@Partition[ Prime[ Range[ 2, 300]], 2, 1], PrimeQ] (* Harvey P. Dale, Nov 28 2018 *) CROSSREFS Cf. A098142. Sequence in context: A179502 A053703 A216559 * A118638 A088460 A168171 Adjacent sequences: A099908 A099909 A099910 * A099912 A099913 A099914 KEYWORD nonn AUTHOR Reinhard Zumkeller, Oct 29 2004 EXTENSIONS More terms from Robert G. Wilson v, Nov 02 2004 Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, May 21 2007 STATUS approved

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Last modified February 29 18:12 EST 2024. Contains 370428 sequences. (Running on oeis4.)