A308289 Lexicographically earliest sequence of distinct nonprimes such that a(n) + a(n+1) is prime.

1, 4, 9, 8, 15, 14, 27, 10, 21, 16, 25, 6, 35, 12, 49, 18, 55, 24, 65, 32, 39, 20, 33, 26, 45, 22, 51, 28, 69, 34, 63, 38, 75, 52, 57, 40, 87, 44, 93, 46, 81, 50, 77, 30, 119, 48, 91, 36, 95, 42, 85, 54, 125, 56, 111, 62, 105, 58, 99, 64, 115, 66, 133, 60, 121, 70, 123, 68, 129, 82, 117, 74, 153, 76, 135, 88, 141, 86, 143, 80, 147, 92

Offset

1,2

Links

Carole Dubois, Table of n, a(n) for n = 1..3654

Example

The sequence starts with 1, 4, 9, 8, 15, 14, 27, 10, 21, 16, 25, ... and we see that:
a(1) + a(2) = 1 + 4 = 5 (a prime);
a(2) + a(3) = 4 + 9 = 13 (a prime);
a(3) + a(4) = 9 + 8 = 17 (a prime);
a(4) + a(5) = 8 + 15 = 23 (a prime); etc.

Crossrefs

Essentially the same as A075570.

Sequence in context: A085084 A248390 A075570 * A236630 A351381 A342551

Adjacent sequences: A308286 A308287 A308288 * A308290 A308291 A308292

Keyword

base,nonn

Author

Eric Angelini and Carole Dubois, May 18 2019

Status

approved