A134854 Least prime of the form 1 + p*2^n, where p is an odd prime.

7, 13, 41, 113, 97, 193, 641, 769, 11777, 13313, 59393, 12289, 40961, 114689, 163841, 2424833, 6946817, 786433, 5767169, 7340033, 23068673, 155189249, 595591169, 1224736769, 167772161, 469762049, 2281701377, 3489660929, 12348030977

Offset: 1

Author

T. D. Noe, Nov 13 2007

Keywords

• nonn

Comments

a(n) least prime such that A098006(pi(a(n))) = 2^(n-1). See A134855 for the values of p.

Links

• T. D. Noe, Table of n, a(n) for n=1..1000

Programs

Mathematica

Table[Select[1+2^n*Prime[Range[2,100]], PrimeQ, 1][[1]], {n,41}]