A113884 Pentanacci analog of A055502.

0, 2, 3, 7, 13, 29, 59, 113, 223, 439, 877, 1721, 3389, 6653, 13093, 25741, 50599, 99487, 195581, 384509, 755959

Offset: 0

Author

Jonathan Vos Post, Jan 27 2006

Keywords

• easy
• nonn

Comments

This is to the pentanacci sequence as A055502 is to the Fibonacci sequence and A113823 is to the tribonacci 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 A113823, least prime greater than the sum of the previous 5 terms in this sequence).

Examples

			a(6) = 59 because a(1)+a(2)+a(3)+a(4)+a(5) = 2+3+7+13+29 = 54, the smallest prime beyond 54 is 59.
a(10) = 877 because a(5)+a(6)+a(7)+a(8)+a(9) = 29 + 59 + 113 + 223 + 439 = 863 is prime, the next prime being 14 more, namely 877.
		

Crossrefs

Cf. A055502, A113823.

Formula

a(-n) = a(0) = 0, a(1) = 2, for n>1: a(n) = smallest prime > a(n-1)+a(n-2)+a(n-3)+a(n-4)+a(n-5).