OFFSET
1,1
COMMENTS
Or, primes of the form prime(n)*prime(n+1)- (prime(n)+prime(n+1))/2.
Subsequence of A099909.
EXAMPLE
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
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