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Prime tribonacci numbers.
10

%I #16 Oct 08 2017 18:04:53

%S 2,7,13,149,19341322569415713958901,15762679542071167858843489,

%T 145082467753351661438130501937754420584096000083183992629

%N Prime tribonacci numbers.

%C The next term has 212 digits and is too large to fit. - _Harvey P. Dale_, Oct 08 2017

%C These primes are A000073(k) at k = 4, 6, 7, 11, 87, 98, 215, 802, 4202, ... The indices in A092835 are off by one. - _R. J. Mathar_, Dec 14 2011

%H Harry J. Smith, <a href="/A092836/b092836.txt">Table of n, a(n) for n = 1..8</a>

%H Tony D. Noe and Jonathan Vos Post, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL8/Noe/noe5.html">Primes in Fibonacci n-step and Lucas n-step Sequences,</a> J. of Integer Sequences, Vol. 8 (2005), Article 05.4.4

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/TribonacciNumber.html">Tribonacci Number</a>

%t Select[LinearRecurrence[{1,1,1},{0,0,1},1000],PrimeQ] (* _Harvey P. Dale_, Oct 08 2017 *)

%o (PARI) t(m)= { if (m==0, return(a1)); if (m==1, return(a2)); if (m==2, return(a3)); r = a1 + a2 + a3; a1=a2; a2=a3; a3=r; return(r); } { a1=0; a2=1; a3=1; n=0; for (m=0, 1000, a=t(m); if (isprime(a), write("b092836.txt", n++, " ", a))); } \\ _Harry J. Smith_, Jun 21 2009

%Y Cf. A000073, A092835, A056816.

%K nonn

%O 1,1

%A _Eric W. Weisstein_, Mar 06 2004