A137451 a(1)=1. a(n) = the smallest integer > a(n-1) such that a(n)+a(k), for some k where 1<=k<=n, is the n-th prime.

1, 2, 3, 4, 7, 9, 10, 12, 13, 16, 18, 19, 22, 24, 25, 28, 31, 33, 34, 37, 39, 40, 43, 46, 51, 55, 57, 61, 63, 67, 70, 74, 76, 78, 79, 81, 83, 84, 86, 87, 92, 94, 97, 99, 100, 102, 109, 114, 118, 120, 124, 125, 127, 131, 132, 136, 137, 139, 140, 141, 142, 151, 156, 160

Offset

1,2

Links

Table of n, a(n) for n=1..64.

Example

103 is the 27th prime. Checking: 103-a(26) = 103-55 = 48, which is <= a(26)=55; so a(27) is not 48. 103-a(25) = 103-51 = 52, which is also <= a(26). But 103-a(24) = 103-46 = 57, which is > a(26). So a(27) is 57 and a(27)+a(24) = the 27th prime = 103.

Maple

A137451 := proc(n) option remember ; local p, o; if n <= 3 then RETURN(n) ; fi ; p := ithprime(n) ; for o from 1 do if p-A137451(n-o) > A137451(n-1) then RETURN( p-A137451(n-o) ) ; fi ; od: end: seq(A137451(n), n=1..120) ; # R. J. Mathar, May 23 2008

Crossrefs

Sequence in context: A096118 A050029 A364868 * A325091 A057912 A141748

Adjacent sequences: A137448 A137449 A137450 * A137452 A137453 A137454

Keyword

nonn

Author

Leroy Quet, Apr 18 2008

Extensions

More terms from R. J. Mathar, May 23 2008

Status

approved