cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A050613 Products of distinct terms of 1 and rest from A001566: a(n) = Product_{i=0..floor(log_2(n+1))} L(2^i)^bit(n,i).

Original entry on oeis.org

1, 1, 3, 3, 7, 7, 21, 21, 47, 47, 141, 141, 329, 329, 987, 987, 2207, 2207, 6621, 6621, 15449, 15449, 46347, 46347, 103729, 103729, 311187, 311187, 726103, 726103, 2178309, 2178309, 4870847, 4870847, 14612541, 14612541, 34095929, 34095929
Offset: 0

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Author

Antti Karttunen, Dec 02 1999

Keywords

Comments

Used to produce the rows of A050609.
Also Sum(((C(2((n+((n+1) mod 2)) mod (2^floor(log_2(n)))),i) mod 2)*F(n+((n+1) mod 2)-i)),i=0..2((n+((n+1) mod 2)) mod (2^floor(log_2(n))))) or Sum(((C(2((n-(n mod 2)) mod (2^floor(log_2(n)))),i) mod 2)*L(n-(n mod 2)-i)),i=0..2((n-(n mod 2)) mod (2^floor(log_2(n))))) for all n > 1. Here F(n) and L(n) are n-th Fibonacci (A000045) and Lucas (A000032) numbers respectively.

Crossrefs

Bisection: A050614.

Programs

  • Maple
    with(combinat); A050613 := n -> product('luc(2^i)^bit_i(n,i)','i'=0..floor_log_2(n+1));
    luc := n -> (fibonacci(n-1)+fibonacci(n+1));
    bit_i := (n,i) -> `mod`(floor(n/(2^i)),2);
    floor_log_2 := proc(n) local nn,i; nn := n; for i from -1 to n do if(0 = nn) then RETURN(i); fi; nn := floor(nn/2); od; end;