A139367 a(n) = A102700(n) - A102342(n).

1, 1, 2, 3, 2, 1, 3, 2, 4, 4, 6, 4, 4, 9, 8, 7, 7, 7, 7, 7, 5, 2, 3, 2, 2, 4, 4, 7, 10, 10, 9, 9, 8, 7, 5, 6, 9, 7, 13, 13, 13, 11, 12, 14, 15, 23, 16, 16, 16, 10, 10, 16, 13, 13, 13, 13, 12, 7, 10, 7, 1, 1, 1, 4, 6, 5, 9, 9, 13, 11, 16, 13, 13, 15, 13, 8, 9, 8, 10, 9, 10, 6, 7, 7, 10, 10, 11, 18

Offset

1,3

Comments

a(332) = -1.

Links

Table of n, a(n) for n=1..88.

Index entries for prime races

Maple

From R. J. Mathar, Apr 25 2010: (Start)
A102700 := proc(n) option remember; if n = 1 then 1; else for a from procname(n-1)+1 do if isprime(10*a+9) then return a; end if; end do: end if; end proc:
A102342 := proc(n) option remember; if n = 1 then 0; else for a from procname(n-1)+1 do if isprime(10*a+7) then return a; end if; end do: end if; end proc:
A139367 := proc(n) A102700(n)-A102342(n) ; end proc: seq(A139367(n), n=1..120) ; (End)

Crossrefs

Sequence in context: A240224 A118105 A125211 * A117648 A037222 A107357

Adjacent sequences: A139364 A139365 A139366 * A139368 A139369 A139370

Keyword

sign

Author

Juri-Stepan Gerasimov, Jun 09 2008

Extensions

Corrected (a 6 replaced by 7, a 7 by 9, a 13 by 16) and extended by R. J. Mathar, Apr 25 2010

Status

approved