A163161 Values of n at which the sequence A161865/A161867 equals 1/2.

5, 9, 14, 30, 44, 47, 64, 67, 72, 89, 99, 124, 125, 194, 198, 200, 208, 213, 214, 249, 267, 270, 320, 333, 372, 373, 374, 393, 455, 460, 475, 519, 586, 603, 643, 701, 704, 712, 770, 774, 789, 814, 825, 828, 836, 891, 906, 930, 941, 970, 974, 982, 983, 988, 1022

Offset: 1

Author

Daniel Tisdale, Jul 21 2009, Jul 24 2009

Keywords

• nonn

Comments

The corresponding sequence for primes is A144264, and the ratio is given by sequences A161621/A161622.

Programs

Mathematica

t1 = Table[ ((2n+1) - (PrimePi[(n+1)^2] - PrimePi[n^2]))/((4n+4)- (PrimePi[(n+2)^2] - PrimePi[n^2])), {n,1,300}]; t2= Position[t1, 1/2] (* Daniel Tisdale, Jul 24 2009 *)

Extensions

Corrected by the author, Jul 25 2009

Extended beyond 194 by R. J. Mathar, Sep 27 2009