A070230 Let S_n ={p_n + q : p_n is the n-th odd prime and q runs through odd primes not greater than p_n}; sequence gives size of S_n intersect S_(n+1).

0, 1, 1, 2, 2, 3, 3, 5, 4, 6, 4, 5, 5, 9, 10, 6, 11, 6, 7, 13, 7, 14, 8, 8, 8, 9, 9, 10, 10, 11, 19, 10, 13, 11, 20, 21, 12, 22, 23, 12, 16, 13, 13, 14, 23, 24, 14, 15, 15, 28, 16, 19, 29, 30, 31, 17, 32, 16, 18, 21, 20, 17, 19, 18, 21, 36, 23, 20, 19, 38, 17, 39, 40, 20, 41, 18, 21

Offset

1,4

Links

Table of n, a(n) for n=1..77.

Example

S_5 = {16,18,20,24,26} and S_6 = {20,22,24,28,30,34} so a(5)=2.

Crossrefs

Sequence in context: A369984 A342515 A307815 * A007150 A213634 A300271

Adjacent sequences: A070227 A070228 A070229 * A070231 A070232 A070233

Keyword

nonn,easy

Author

Jeremiah K. Hower (jhower(AT)vt.edu), May 07 2002

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Sep 26 2002

Status

approved