

A154800


List of pairs of primes that are equidistant from and nearest to n, or the pair (0,0) if there is no such pair.


1



0, 0, 0, 0, 0, 0, 3, 5, 3, 7, 5, 7, 3, 11, 5, 11, 7, 11, 7, 13, 5, 17, 11, 13, 7, 19, 11, 17, 13, 17, 13, 19, 11, 23, 17, 19, 7, 31, 17, 23, 19, 23, 13, 31, 17, 29, 19, 29, 19, 31, 23, 29, 23, 31, 19, 37, 17, 41, 29, 31, 19, 43, 23, 41, 29, 37, 31, 37, 29, 41, 31, 41, 31, 43, 29, 47
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OFFSET

1,7


COMMENTS

Conjecture: There are only six 0's in this sequence.


LINKS

Table of n, a(n) for n=1..76.


EXAMPLE

Array begins:
n ............... Pair
1 .............. 0 . 0
2 .............. 0 . 0
3 .............. 0 . 0
4 .............. 3 . 5
5 ............ 3 . . . 7
6 .............. 5 . 7
7 ........ 3 . . . . . . . 11
8 .......... 5 . . . . . 11
9 ............ 7 . . . 11
10 ......... 7 . . . . . 13


MAPLE

A154800 := proc(n) local d; for d from 1 to n1 do if isprime(nd) and isprime(n+d) then printf("%d, %d, ", nd, n+d); RETURN() ; fi; od: printf("0, 0, ") ; end: seq(A154800(n), n=1..80) ; # R. J. Mathar, Jul 13 2009


CROSSREFS

Cf. A154720, A154721, A154722, A154723, A154724, A154725, A154726, A154727.
Sequence in context: A144294 A255313 A305883 * A263175 A137768 A137769
Adjacent sequences: A154797 A154798 A154799 * A154801 A154802 A154803


KEYWORD

nonn,tabf


AUTHOR

Omar E. Pol, Jan 15 2009, Jan 18 2009


EXTENSIONS

More terms from R. J. Mathar, Jul 13 2009


STATUS

approved



