A202113 Numbers n such that 90n + 61 is prime.

0, 1, 2, 3, 4, 6, 7, 11, 13, 14, 20, 21, 23, 24, 25, 29, 31, 34, 36, 37, 39, 43, 44, 45, 46, 50, 51, 53, 55, 56, 58, 62, 64, 67, 69, 70, 71, 77, 81, 84, 90, 93, 94, 99, 101, 102, 104, 105, 106, 108, 109, 112, 114, 116, 119, 120, 123, 125, 127, 132, 135, 136

Offset

1,3

Comments

This sequence was generated by adding 14 Fibonacci-like sequences [See: PROG]. Looking at the format 90n+61 modulo 9 and modulo 10 we see that all entries of A142330 have digital root 7 and last digit 1. (Reverting the process is an application of the Chinese remainder theorem.) The 14 Fibonacci-like sequences are generated (via the p and q values given in the Perl program) from the base p,q pairs 61*91, 19*79, 37*43, 73*7, 11*71, 29*89, 47*53, 83*17, 13*67, 31*31, 49*49, 23*77, 41*41, 59*59.

Links

Table of n, a(n) for n=1..62.

Mathematica

Select[Range[0, 200], PrimeQ[90 # + 61] &]

Prog

(PARI) is(n)=isprime(90*n+61) \\ Charles R Greathouse IV, Feb 17 2017

Crossrefs

Cf. A181732, A198382, A195993, A196000, A196007, A201739, A201734, A201804, A201816, A201817, A201818, A201820, A201822, A202101, A202104, A202105, A202110, A202112.

Sequence in context: A226538 A339510 A191930 * A113243 A130690 A308189

Adjacent sequences: A202110 A202111 A202112 * A202114 A202115 A202116

Keyword

nonn,easy

Author

J. W. Helkenberg, Dec 11 2011

Status

approved