OFFSET
0,2
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).
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).
EXAMPLE
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
KEYWORD
easy,nonn
AUTHOR
Jonathan Vos Post, Jan 27 2006
STATUS
approved