A201804 Numbers k such that 90*k + 11 is prime.

0, 1, 2, 3, 5, 7, 9, 10, 12, 13, 15, 16, 19, 20, 21, 23, 26, 27, 28, 29, 30, 31, 36, 41, 43, 47, 49, 52, 54, 56, 58, 61, 62, 65, 68, 69, 70, 72, 73, 75, 79, 80, 83, 87, 90, 92, 97, 98, 100, 103, 104, 105, 106, 112, 113, 114, 118, 124, 125

Offset: 1

Author

J. W. Helkenberg, Dec 05 2011

Keywords

• nonn
• easy

Comments

This sequence was generated by adding 12 Fibonacci-like sequences. Looking at 90*k+11 modulo 9 and modulo 10 we see that all entries of A142317 have digital root 2 and last digit 1. (Reverting the process is an application of the Chinese remainder theorem)

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A181732, A198382, A195993, A196000, A196007, A201739, A201734.

Programs

Magma

[n: n in [0..200] | IsPrime(90*n+11)]; // Vincenzo Librandi, Dec 11 2011

Mathematica

Select[Range[0,40000],PrimeQ[90 #+11]&] (* Vincenzo Librandi, Dec 11 2011 *)

Extensions

a(24)-a(59) from Vincenzo Librandi, Dec 11 2011