cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A161671 a(n) = prime(n) - A141468(n).

Original entry on oeis.org

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
Offset: 1

Views

Author

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

Keywords

Examples

			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.
		

Crossrefs

Programs

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

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

A220220 Primes p of the form p = A161671(k) = A161671(k+1).

Original entry on oeis.org

2, 7, 43, 311, 491, 827, 1367, 1693, 1733, 1741, 2089, 2239, 2927, 3343, 5231, 5743, 9319, 9521, 11177, 12611, 13249, 15511, 16661, 17989, 24083, 24611, 25679, 25841, 28723, 37861, 39199, 46663, 47279, 51659, 53281, 58031, 58309, 58549, 59723, 64091, 68041, 70051, 70913, 71261
Offset: 1

Views

Author

Juri-Stepan Gerasimov, Dec 07 2012

Keywords

Comments

There are also composites m = A161671(k) = A161671(k+1). An example is 65 = A161671(26) = A161671(27). - Michael De Vlieger, Mar 22 2022

Examples

			The prime 2 is in the sequence because 2 = A161671(1) = A161671(2).
		

Crossrefs

Programs

  • Mathematica
    f[n_] := FixedPoint[n + PrimePi@ # &, n + PrimePi@ n]; Reap[Do[(If[PrimeQ[#] && # == j, Sow[#]]; j = #) &[Prime[i] - f[i - 1] ], {i, 8500}] ][[-1, -1]] (* Michael De Vlieger, Mar 22 2022, after Robert G. Wilson v at A141468 *)
Showing 1-2 of 2 results.