A219674 - OEIS

%I #11 Nov 29 2012 12:31:49

%S 1,3,5,7,13,19,17,11,23,31,67,41,29,43,47,37,71,53,61,59,73,101,79,89,

%T 97,83,109,113,107,151,127,103,131,149,137,139,163,173,157,179,167,

%U 181,193,191,197,229,199,223,239,227,241,233,211,251,257,271,269,313,263

%N a(n) = smallest prime not included earlier such that a(n-4) + a(n-3) + a(n-2) + a(n-1) + a(n) is a prime, with a(1)=1, a(2)=3, a(3)=5, and a(4)=7.

%t f[s_List] := Block[{pn = s[[-4]] + s[[-3]] + s[[-2]] + s[[-1]], p = 2}, While[ MemberQ[s, p] || ! PrimeQ[p + pn], p = NextPrime@ p]; Append[s, p]]; Nest[f, {1, 3, 5, 7}, 55]

%Y Cf. A073653.

%K easy,nonn

%O 1,2

%A _Robert G. Wilson v_, Nov 28 2012