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.

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A162832 The odd nonprimes in A162939.

Original entry on oeis.org

1, 35, 65, 119, 125, 155, 161, 209, 245, 287, 299, 335, 341, 377, 395, 407, 425, 497, 539, 551, 575, 629, 665, 695, 731, 737, 749, 755, 785, 845, 899, 965, 989, 1025, 1037, 1079, 1115, 1127, 1235, 1241, 1295, 1325, 1331, 1379, 1421, 1457, 1475, 1529, 1547, 1577
Offset: 1

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Author

Juri-Stepan Gerasimov, Jul 14 2009

Keywords

Comments

Intersection of A014076 and A162939.

Crossrefs

Cf. A000040, A005408, A014076, A162939.

Extensions

Definition simplified, 507 removed, extended by R. J. Mathar, Aug 12 2009

A168565 Let p = prime(n); then a(n) = p + (p-1)/2.

Original entry on oeis.org

4, 7, 10, 16, 19, 25, 28, 34, 43, 46, 55, 61, 64, 70, 79, 88, 91, 100, 106, 109, 118, 124, 133, 145, 151, 154, 160, 163, 169, 190, 196, 205, 208, 223, 226, 235, 244, 250, 259, 268, 271, 286, 289, 295, 298, 316, 334, 340, 343, 349, 358, 361, 376, 385, 394, 403
Offset: 2

Views

Author

Vladimir Joseph Stephan Orlovsky, Nov 30 2009

Keywords

Comments

Also numbers n such that (2n + 1)/3 is prime. - Vicente Izquierdo Gomez, Dec 30 2012

Examples

			3+2/2=4, 5+4/2=7, 7+6/2=10, 11+10/2=16,..

Crossrefs

Cf. A162939.

Programs

  • Mathematica
    f[n_]:=n/2; lst={};Do[p=Prime[n];AppendTo[lst,p+f[p-1]],{n,2,5!}];lst
#+(#-1)/2&/@Prime[Range[2,60]] (* Harvey P. Dale, Nov 04 2017 *)

Formula

a(n) = (3*prime(n)-1)/2.

Extensions

Edited by N. J. A. Sloane, Jan 04 2013
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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