A228520 - OEIS

A228520

a(n) is the smallest number such that if x >= a(n), then pi^*(x) - pi^*(x/2) >= n, where pi^*(x) is the number of terms of A050376 <= x.

2, 3, 11, 16, 23, 41, 47, 59, 67, 71, 79, 101, 107, 109, 127, 149, 167, 169, 179, 181, 227, 229, 233, 239, 256, 263, 269, 281, 283, 307, 347, 349, 359, 367, 373, 401, 409, 419, 431, 433, 439, 461, 487, 491, 521, 569, 587, 593, 599, 601, 607, 617, 641, 643, 647

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OFFSET

1,1

COMMENTS

The sequence is a Fermi-Dirac analog of Ramanujan numbers (A104272), since terms of A050376 play a role of primes in Fermi-Dirac arithmetic (see comments in A050376).

LINKS

Peter J. C. Moses, Table of n, a(n) for n = 1..10000

FORMULA

a(n)<= R_n, where R_n is the n-th Ramanujan number (A104272); a(n)~A000040(2*n) as n goes to infinity.

CROSSREFS

Cf. A104272.

Sequence in context: A076514 A071012 A354742 * A361127 A280969 A349565

Adjacent sequences: A228517 A228518 A228519 * A228521 A228522 A228523

KEYWORD

nonn

AUTHOR

Vladimir Shevelev, Aug 24 2013

EXTENSIONS

More terms from Peter J. C. Moses

STATUS

approved