Hi to all dear seqfans. What I proposed to you today is an old interest for me. I didn't find anything matching in OEIS with this sequence so I hope you will find it interesting.
Fibonacci sequence and the extension
…,-21,13,-8,5,-3,2,-1,1,0,1,1,2,3,5,8,13,21,...
how many times does the value appear
…
-21=1
-8=1
-3=1
-1=1
0=1
1=3
2=2
3=1
5=2
8=1
13=2
21=1
…
right to left: a(n) = a(n-1)*3 + a(n-2)*2 + a(n-3) + a(n-5)*2 + a(n-8) + a(n-13)*2 + a(n-21)+ …
and left to right:
a(n) = a(n+1) + a(n+3) + a(n+8) + a(n+21) + …
i don’t know but in this case a(n +/- 0) i considered that the value must be multiplied by 2
the sequence
1,8,54,468,3150,...
All the best
Davide