login
Prime differences of tetranacci numbers.
4

%I #8 Oct 04 2014 10:17:59

%S 2,3,7,11,13,41,79,107,179,193,293,397,769,1489,2099,2843,2857,5507,

%T 5521,9181,10463,10663,10667,19079,39619,76423,126743,146539,147283,

%U 147311,281081,283949,547229,771073,3919171,3919543,3919943,7555879,7555927,10644589,14564477

%N Prime differences of tetranacci numbers.

%C A113188-A113194 deal with difference sets of Fibonacci numbers and Lucas numbers and primes in those difference sets. A113238-A113239 deal with the difference set of tribonacci numbers and primes in that difference set.

%F {a(n)} = intersection of A000040 and A113243. {a(n)} = primes in the difference set of tetranacci sequence A000078, excluding prime tetranacci numbers A104535.

%e a(1) = 2 because 4 - 2 = 2 where 4 and 2 are tetranacci numbers.

%e a(2) = 3 because 4 - 1 = 3 where 4 and 1 are tetranacci numbers.

%e a(3) = 7 because 8 - 1 = 7 where 8 and 1 are tetranacci numbers.

%e a(4) = 11 because 15 - 4 = 11 where 15 and 4 are tetranacci numbers.

%e a(5) = 13 because 15 - 2 = 13 where 15 and 2 are tetranacci numbers.

%p isA113244 := proc(n)

%p isprime(n) and isA113243(n) ;

%p end proc:

%p for n from 1 do

%p p := ithprime(n) ;

%p if isA113244(p) then

%p printf("%d\n",p) ;

%p end if;

%p end do: # _R. J. Mathar_, Oct 04 2014

%Y Cf. A000040, A000078, A113188-A113194, A113238, A113239, A113243.

%K easy,nonn

%O 1,1

%A _Jonathan Vos Post_, Oct 19 2005; corrected Oct 20 2005

%E 281081 inserted by _R. J. Mathar_, Oct 04 2014