A161671 - OEIS

A161671

a(n) = prime(n) - A141468(n).

2, 2, 1, 1, 3, 4, 7, 7, 9, 14, 15, 19, 21, 22, 25, 29, 34, 35, 40, 43, 43, 47, 50, 55, 62, 65, 65, 68, 69, 71, 83, 86, 91, 91, 100, 101, 106, 111, 113, 118, 123, 124, 133, 133, 135, 136, 147, 158, 161, 161, 164, 169, 169, 177, 182, 187, 192, 193, 197, 200, 201, 209

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Michael De Vlieger, Table of n, a(n) for n = 1..10000

Michael De Vlieger, Scatterplot of a(n), n = 1..120, showing and labeling primes p (in A214627) in red and blue, the red primes are duplicated and are listed in A220220. We plot in green duplicated composite terms.

FORMULA

a(n) = A000040(n) - A141468(n).

a(n+2) = A168563(n).

a(n) = A000040(n) - A018252(n-1), if n >= 2. - Omar E. Pol, Oct 21 2011

a(n) ~ n log n. - Charles R Greathouse IV, Dec 21 2011

EXAMPLE

2(=2-0), 2(=3-1), 1(=5-4), 1(=7-6), 3(=11-8), 4(=13-9), 7(=17-10), 7(=19-12), 9(=23-14), 14(=29-15), etc.

MAPLE

A161671 := proc(n)

ithprime(n)-A141468(n) ;

end proc: # R. J. Mathar, Aug 08 2012

MATHEMATICA

f[n_] := FixedPoint[n + PrimePi@ # &, n + PrimePi@ n]; Array[Prime[#] - f[# - 1] &, 62] (* Michael De Vlieger, Mar 22 2022, after Robert G. Wilson v at A141468 *)

CROSSREFS

Cf. A000040, A002808, A141468, A141559, A168563, A214627, A220220.

Sequence in context: A237597 A034928 A280267 * A144444 A054106 A132044

Adjacent sequences: A161668 A161669 A161670 * A161672 A161673 A161674

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Jun 16 2009, Dec 03 2009.

EXTENSIONS

Edited by N. J. A. Sloane, Jun 30 2009

207 replaced with 209 by R. J. Mathar, Oct 04 2009

Edited by Omar E. Pol, Oct 21 2011

STATUS

approved