

A087516


Consider pairs (i,j) such that j*P(i)#  P(i+2) and j*P(i)#  P(i+1) are consecutive primes and 0 < j < P(i+1), where P(r) = rth prime and P(r)# = rth primorial number (A002110). Sequence gives i values.


2



5, 5, 5, 7, 7, 7, 7, 7, 7, 11, 13, 13, 13, 13, 13, 17, 17, 17, 17, 17, 19, 23, 23, 29, 29, 31, 37, 37, 37, 43, 43, 43, 47, 47, 59, 61, 61, 61, 67, 67, 67, 73, 79, 79, 83, 83, 89, 89, 97, 97, 103, 109, 127, 131, 131, 137, 137, 151, 163, 163, 167, 167, 173, 173, 173, 179, 179
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OFFSET

0,1


LINKS

Table of n, a(n) for n=0..66.


EXAMPLE

1*2*3*5  11 = 19, 1*2*3*5  7 = 23, 19 and 23 consecutive primes;
3*2*3*5  11 = 79, 3*2*3*5  7 = 83, 79 and 83 consecutive primes;
4*2*3*5  11 = 109, 4*2*3*5  7 = 113, 109 and 113 consecutive primes;
so 5 = P(3) is the first term in the sequence and occurs 3 times for j=1,3,4.


CROSSREFS

A087517 gives j values.
Sequence in context: A266948 A176172 A204911 * A194428 A299695 A135089
Adjacent sequences: A087513 A087514 A087515 * A087517 A087518 A087519


KEYWORD

nonn


AUTHOR

Pierre CAMI, Oct 23 2003


STATUS

approved



