A202104 Numbers k such that 90*k + 41 is prime.

0, 1, 3, 4, 5, 8, 10, 11, 14, 16, 17, 21, 23, 26, 30, 33, 35, 37, 38, 42, 43, 44, 45, 47, 49, 52, 56, 57, 58, 59, 60, 61, 63, 64, 66, 72, 74, 75, 77, 79, 81, 85, 91, 94, 96, 98, 99, 100, 102, 103, 105, 109, 110, 113, 114, 115, 127, 131, 133, 134, 136, 140

Offset: 1

Author

J. W. Helkenberg, Dec 11 2011

Keywords

• nonn
• easy
• changed

Comments

This sequence was generated by adding 12 Fibonacci-like sequences [See: PROG]. Looking at the format 90k+41 modulo 9 and modulo 10 we see that all entries of A142333 have digital root 5 and last digit 1. (Reverting the process is an application of the Chinese remainder theorem.) The 12 Fibonacci-like sequences are generated (via the PERL program) from the base pairs 49*91, 19*59, 37*23, 73*77, 11*61, 29*79, 47*43, 83*7, 13*17, 31*71, 49*89, 67*53.

Crossrefs

Cf. A181732, A198382, A195993, A196000, A196007, A201739, A201734, A201804, A201816, A201817, A201818, A201820, A201822, A202101.

Programs

Mathematica

Select[Range[0, 200], PrimeQ[90 # + 41] &]

PARI

is(n)=isprime(90*n+41) \\ Charles R Greathouse IV, Feb 17 2017