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A126072
a(n) = least j>n such that one of p(n)#+p(j)#-1 and p(n)#+p(j)#+1 is prime, or 0 if no such prime exists.
0
2, 3, 4, 5, 6, 7, 9, 9, 15, 11, 13, 13, 18, 20, 29, 19, 23, 21, 21, 21, 23, 32, 27, 42, 28, 30, 30, 34, 37, 77, 33, 74, 59, 45, 53, 45, 38, 46, 43, 47, 55, 44, 47, 54, 76, 48, 49, 50, 69, 56, 60, 0, 66, 68, 94, 57, 69, 84, 86, 73, 65, 73, 71, 114, 70, 91, 98, 80, 72, 84, 79, 76
OFFSET
1,1
COMMENTS
The first 0 is for n=52. Are there others?
EXAMPLE
2+2*3-1 = 7 so a(1) = 2.
2*3+2*3*5-1 = 35 is composite but 2*3+2*3*5+1 = 37 is prime so a(2) = 3.
CROSSREFS
Sequence in context: A071191 A300903 A097428 * A265570 A265554 A082463
KEYWORD
nonn
AUTHOR
Pierre CAMI, Mar 01 2007
STATUS
approved