A083201 a(1) = 1. For n>1, let x = a(n-1)+1; then a(n) is the first prime in the sequence 2*x-1, 2*x-3, 4*x-1, 4*x-3, 8*x-1, 8*x-3, ..., (2^k)*x-1, (2^k)*x-3, ...

1, 3, 7, 13, 53, 107, 431, 863, 6911, 27647, 442367, 7247757311, 3710851743743, 7421703487487, 31875973759370105192447, 71778311772385457136805581255138607103

Offset

1,2

Links

Table of n, a(n) for n=1..16.

Example

a(9) = 6911 because a(8)=863 and its sequence starts 1727, 1725, 3455, 3453, 6911, ...; 6911 is the first prime.

Crossrefs

Cf. A084361.

Sequence in context: A062736 A257716 A103564 * A228209 A176903 A004060

Adjacent sequences: A083198 A083199 A083200 * A083202 A083203 A083204

Keyword

nonn

Author

Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Apr 27 2003

Extensions

Edited by Don Reble, Jun 20 2003

Status

approved