A113823 Tribonacci analog of A055502.

0, 2, 3, 7, 13, 29, 53, 97, 181, 337, 617, 1151, 2111, 3881, 7151, 13147, 24181, 44483, 81817, 150497, 276817, 509137, 936469, 1722431, 3168097, 5827001, 10717561, 19712669, 36257237, 66687469, 122657377, 225602099, 414946951, 763206467, 1403755531, 2581909003

Offset

0,2

Comments

This is to the tribonacci sequence as A055502 is to the Fibonacci sequence (i.e. least prime greater than the sum of the previous 2 terms in A055502, least prime greater than the sum of the previous 3 terms in this sequence).

The first 9 positive terms are also elements of A089189 but that coincidence breaks down as a(10) = 617 is a prime p, but p-1 = 616 = 2^3 * 7 * 11 is not cubefree.

Links

Amiram Eldar, Table of n, a(n) for n = 0..1000

Formula

a(0) = 0, a(1) = 2, for n>2: a(n) = smallest prime > a(n-1)+a(n-2)+a(n-3).

Mathematica

a[0] = 0; a[1] = 2; a[2] = 3; a[n_] := a[n] = NextPrime[a[n-1] + a[n-2] + a[n-3]]; Array[a, 40, 0] (* Amiram Eldar, Sep 24 2023 *)

Crossrefs

Cf. A055502, A089189.

Sequence in context: A233350 A233557 A296415 * A113843 A199582 A255516

Adjacent sequences: A113820 A113821 A113822 * A113824 A113825 A113826

Keyword

easy,nonn

Author

Jonathan Vos Post, Jan 23 2006

Extensions

More terms from Amiram Eldar, Sep 24 2023

Status

approved