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A180944
Primes such that their product with the successive prime plus the next successive prime plus 1 is a prime.
5
3, 5, 13, 17, 19, 29, 41, 47, 61, 67, 73, 97, 103, 107, 157, 191, 229, 277, 281, 283, 293, 307, 379, 401, 409, 491, 547, 557, 569, 607, 619, 659, 691, 701, 751, 773, 787, 823, 827, 853, 883, 887, 911, 971, 983, 997, 1031, 1039, 1049, 1109, 1129, 1153, 1171
OFFSET
1,1
COMMENTS
prime(i)*prime(i+1) + prime(i+2) + 1 is prime.
In the sequence there are some twins: e.g. (281, 283) and (1949, 1951).
There are also successive primes such as (13,17,19); (277,281,283,293,307); (883,887).
EXAMPLE
a(5)=19 since 19*23+29+1=467 is a prime.
MATHEMATICA
#[[1]]&/@Select[Partition[Prime[Range[200]], 3, 1], PrimeQ[ #[[1]] #[[2]]+#[[3]]+1]&] (* Harvey P. Dale, Nov 07 2010 *)
CROSSREFS
Cf. A000040.
Sequence in context: A090545 A045411 A184796 * A049282 A003625 A105900
KEYWORD
nonn
AUTHOR
Carmine Suriano, Sep 27 2010
EXTENSIONS
Missing values starting at 1031 inserted by R. J. Mathar, Oct 18 2010
STATUS
approved