A274986 Numbers k such that (10^k + 23)/3 is prime.

1, 2, 6, 146, 326, 380, 1116, 1866, 4808, 5528, 5730, 21836, 24804, 38724

Offset: 1

Author

Vincenzo Librandi, Sep 25 2016

Keywords

• nonn
• less
• more

Comments

Also numbers k for which A093137(k) + 7 or A002277(k) + 8 is prime.

Crossrefs

Cf. numbers k such that (10^k+m)/3 is prime: A099411 (m=11), this sequence (m=23).

Cf. A002277, A093137.

Programs

Magma

[n: n in [0..400] | IsPrime((10^n+23) div 3)];

Mathematica

Select[Range[1000], PrimeQ[(10^# + 23) / 3] &]

PARI

is(n)=ispseudoprime((10^n+23)/3) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

a(9)-a(11) from Michael S. Branicky, Aug 16 2021

a(12)-a(13) from Michael S. Branicky, May 14 2023

a(14) from Kamada data by Tyler Busby, May 05 2024