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Tetranacci analog of A055502.
1

%I #12 Jul 10 2015 19:54:52

%S 0,2,3,7,13,29,53,103,199,389,751,1447,2789,5381,10369,19991,38543,

%T 74287,143197,276019,532061,1025579,1976857,3810517,7345031,14158009,

%U 27290429,52604017,101397487,195449957,376741891,726193373,1399782719,2698167947,5200885961

%N Tetranacci analog of A055502.

%C This is to the tribonacci 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 4 terms in this sequence).

%H Harvey P. Dale, <a href="/A113843/b113843.txt">Table of n, a(n) for n = 0..1000</a>

%F 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).

%e a(15) = 19991 because a(11)+a(12)+a(13)+a(14) = 1447 + 2789 + 5381 + 10369 = 19986 and 19991 is the smallest prime > 19986.

%t nxt[{a_,b_,c_,d_}]:={b,c,d,NextPrime[a+b+c+d]}; Transpose[ NestList[ nxt,{0,2,3,7},40]][[1]] (* _Harvey P. Dale_, Sep 18 2013 *)

%Y Cf. A055502, A113823.

%K easy,nonn

%O 0,2

%A _Jonathan Vos Post_, Jan 24 2006

%E More terms from _Harvey P. Dale_, Sep 18 2013