A126092 - OEIS

%I #7 Jun 09 2018 10:45:03

%S 2,3,5,7,13,23,41,73,131,241,443,811,1493,2741,5039,9257,17033,31327,

%T 57601,105953,194869,358417,659237,1212521,2230159,4101907,7544573,

%U 13876601,25523011,46944179,86343787,158810947,292098907,537253631

%N a(1)=2, a(2)=3, a(3)=5; a(n) = largest prime < a(n-1)+a(n-2)+a(n-3).

%H Robert Israel, <a href="/A126092/b126092.txt">Table of n, a(n) for n = 1..3775</a>

%p f:= proc(n) option remember; prevprime(procname(n-1)+procname(n-2)+procname(n-3)) end proc:

%p f(1):= 2: f(2):= 3: f(3):= 5:

%p map(f, [$1..100]); # _Robert Israel_, Mar 12 2018

%t nxt[{a_,b_,c_}]:={b,c,NextPrime[a+b+c,-1]}; NestList[nxt,{2,3,5},40][[All,1]] (* _Harvey P. Dale_, Jun 09 2018 *)

%Y Cf. A055501.

%K nonn

%O 1,1

%A _Zak Seidov_, Mar 03 2007