A086304 -id:A086304 - cp's OEIS frontend

A089038 Nonnegative numbers k such that 2k+5 is prime.

0, 1, 3, 4, 6, 7, 9, 12, 13, 16, 18, 19, 21, 24, 27, 28, 31, 33, 34, 37, 39, 42, 46, 48, 49, 51, 52, 54, 61, 63, 66, 67, 72, 73, 76, 79, 81, 84, 87, 88, 93, 94, 96, 97, 103, 109, 111, 112, 114, 117, 118, 123, 126, 129, 132, 133, 136, 138, 139, 144, 151, 153, 154, 156, 163

Offset: 1

Ray Chandler, Nov 29 2003

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Cf. A086304.
Numbers n such that 2n+k is prime: A005097 (k=1), A067076 (k=3), this seq (k=5), A105760 (k=7), A155722 (k=9), A101448 (k=11), A153081 (k=13), A089559 (k=15), A173059 (k=17), A153143 (k=19).
Numbers n such that 2n-k is prime: A006254 (k=1), A098090 (k=3), A089253 (k=5), A089192 (k=7), A097069 (k=9), A097338 (k=11), A097363 (k=13), A097480 (k=15), A098605 (k=17), A097932 (k=19).

Filtered([0..200], k-> IsPrime(2*k+5) ); # G. C. Greubel, May 21 2019

[n: n in [0..200]| IsPrime(2*n+5)]; // Vincenzo Librandi, Nov 17 2010

(Prime[Range[3,100]]-5)/2 (* Vladimir Joseph Stephan Orlovsky, Feb 08 2010 *)
Select[Range[0, 200], PrimeQ[2*# + 5] &] (* Vincenzo Librandi, Oct 16 2012 *)

is(n)=isprime(2*n+5) \\ Charles R Greathouse IV, Feb 16 2017

[n for n in (0..200) if is_prime(2*n+5) ] # G. C. Greubel, May 21 2019

a(n) = (A086304(n-1) + 1)/2, n > 1.

Removed wrong comment by Ralf Stephan, Nov 17 2010

Definition clarified by Zak Seidov, Jul 11 2014

A166457 Numbers n such that n*100+1 is prime.

Original entry on oeis.org

1, 4, 6, 7, 12, 13, 16, 18, 19, 28, 30, 33, 37, 40, 42, 48, 51, 55, 57, 58, 61, 63, 67, 70, 79, 81, 85, 90, 96, 99, 103, 105, 106, 117, 118, 121, 123, 124, 126, 130, 139, 144, 151, 154, 156, 159, 160, 163, 169, 174, 183, 184, 187, 190, 193, 195, 198, 201, 202, 210, 211

Offset: 1

Juri-Stepan Gerasimov, Oct 14 2009

			a(1)=1 (1*100+1=prime); a(2)=4 (4*100+1=prime).

G. C. Greubel, Table of n, a(n) for n = 1..10000

Cf. A000040, A086304.

a := proc (n) if isprime(100*n+1) then n else end if end proc: seq(a(n), n = 1 .. 250); # Emeric Deutsch, Nov 01 2009

Select[If[PrimeQ[100*# + 1], #] & /@ Range[2*8!], IntegerQ] (* G. C. Greubel, May 15 2016 *)

is(n)=isprime(n*100+1) \\ Charles R Greathouse IV, Jun 13 2017

Extended by Emeric Deutsch, Nov 01 2009

cp's OEIS Frontend

A089038 Nonnegative numbers k such that 2k+5 is prime.

Views

Author

Keywords

Links

Crossrefs

Programs

GAP

Magma

Mathematica

PARI

Sage

Formula

Extensions