A105106 Numbers k such that the string k101 is prime.

0, 5, 6, 8, 12, 15, 20, 21, 29, 42, 44, 50, 53, 54, 56, 60, 65, 72, 74, 77, 78, 81, 83, 89, 95, 98, 102, 107, 116, 117, 119, 125, 131, 135, 138, 141, 149, 170, 174, 177, 182, 194, 197, 201, 204, 210, 221, 224, 230, 240, 242, 243, 252, 258, 261, 263, 264, 282, 285, 291

Offset

1,2

Comments

Also numbers k such that 1000*k + 101 is prime. - Stefan Steinerberger, Feb 21 2006

Links

Daniel Starodubtsev, Table of n, a(n) for n = 1..10000

Example

If k=0,  then k101 =  0101 (prime).
If k=42, then k101 = 42101 (prime).

Maple

q:= n-> isprime(parse(cat(n, 101))):
select(q, [$0..300])[];  # Alois P. Heinz, Jan 23 2020

Mathematica

For[n = 0, n < 300, n++, If[PrimeQ[1000*n + 101], Print[n]]] (* Stefan Steinerberger, Feb 21 2006 *)

Prog

(PARI) is(n)=isprime(1000*n+101) \\ Charles R Greathouse IV, May 22 2017

Crossrefs

Sequence in context: A033158 A193569 A032721 * A140504 A120131 A047437

Adjacent sequences: A105103 A105104 A105105 * A105107 A105108 A105109

Keyword

base,nonn

Author

Parthasarathy Nambi, Apr 07 2005

Extensions

More terms from Stefan Steinerberger, Feb 21 2006

Missing a(11)=44 inserted by Daniel Starodubtsev, Jan 23 2020

Status

approved