login
Differences of nonzero tetranacci numbers.
2

%I #19 Jun 23 2024 11:44:38

%S 0,1,2,3,4,6,7,11,13,14,21,25,27,28,41,48,52,54,55,79,93,100,104,106,

%T 107,152,179,193,200,204,206,207,293,345,372,386,393,397,399,400,565,

%U 665,717,744,758,765,769,771,772,1089,1282,1382,1434,1461,1475,1482

%N Differences of nonzero tetranacci numbers.

%H R. J. Mathar, <a href="/A113243/b113243.txt">Table of n, a(n) for n = 1..197</a>

%F {a(n)} = { A000078(i) - A000078(j) such that i>=j>=3 }.

%p isA113243 := proc(n)

%p local i,j ;

%p for j from 3 do

%p for i from 3 to j do

%p if A000078(j) - A000078(i) = n then

%p return true;

%p elif A000078(j) - A000078(i) < n then

%p break ;

%p end if;

%p end do:

%p if A000078(j) - A000078(j-1) > n then

%p return false;

%p end if;

%p end do:

%p end proc:

%p for n from 0 to 10000 do

%p if isA113243(n) then

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

%p end if;

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

%t Union[Flatten[Differences/@Subsets[Drop[LinearRecurrence[{1, 1, 1,1}, {0,0, 0, 1}, 16],3],{2}]]] (* _James C. McMahon_, Jun 23 2024 *)

%Y Cf. A000078, A113244.

%K easy,nonn

%O 1,3

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