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Square array read by antidiagonals: Fibonacci(k*n).
6

%I #22 Sep 08 2022 08:45:16

%S 1,1,1,2,3,2,3,8,8,3,5,21,34,21,5,8,55,144,144,55,8,13,144,610,987,

%T 610,144,13,21,377,2584,6765,6765,2584,377,21,34,987,10946,46368,

%U 75025,46368,10946,987,34,55,2584,46368,317811,832040,832040,317811,46368,2584,55

%N Square array read by antidiagonals: Fibonacci(k*n).

%D R. L. Graham, D. E. Knuth and O. Patashnik, Concrete Mathematics. 2nd Edition. Addison-Wesley, Reading, MA, 1994, p. 294.

%H Freddy Barrera, <a href="/A102310/b102310.txt">Antidiagonals n = 1..50, flattened</a>

%F For prime p, the formula holds: Fibonacci(k*p) = Fibonacci(p) * Sum_{i=0..floor((k-1)/2)} C(k-i-1, i)*(-1)^(i*p+i)*Lucas(p)^(k-2i-1).

%F A(n, k) = F((n-1)*k)*F(k+1) + F((n-1)*k-1)*F(k), where F(n) = A000045(n). - _Freddy Barrera_, Jun 24 2019

%e 1, 1, 2, 3, 5, ...

%e 1, 3, 8, 21, 55, ...

%e 2, 8, 34, 144, 610, ...

%e 3, 21, 144, 987, 6765, ...

%e 5, 55, 610, 6765, 75025, ...

%t Table[Fibonacci[k*(n-k+1)], {n, 1, 10}, {k, 1, n}] // Flatten (* _Jean-François Alcover_, Jun 10 2017 *)

%o (Sage)

%o F = fibonacci # A000045

%o def A(n, k):

%o return F((n-1)*k)*F(k+1) + F((n-1)*k - 1)*F(k)

%o [A(n, k) for d in (1..10) for n, k in zip((d..1, step=-1), (1..d))] # _Freddy Barrera_, Jun 24 2019

%o (Magma) /* As triangle */ [[Fibonacci(k*(n-k+1)): k in [1..n]]: n in [1.. 15]]; // _Vincenzo Librandi_, Jul 04 2019

%Y Equals A000045(A003991(k, n)).

%Y Columns include A000045, A001906, A014445, A033888, A102312.

%Y Main diagonal is in A054783. Antidiagonal sums are in A102311.

%K nonn,tabl

%O 1,4

%A _Ralf Stephan_, Jan 06 2005