A120255 Array read by rows, where the n-th row (of A120256(n) terms) lists the positive divisors, not occurring earlier in the array, of the n-th Fibonacci number.
1, 2, 3, 5, 4, 8, 13, 7, 21, 17, 34, 11, 55, 89, 6, 9, 12, 16, 18, 24, 36, 48, 72, 144, 233, 29, 377, 10, 61, 122, 305, 610, 47, 141, 329, 987, 1597, 19, 38, 68, 76, 136, 152, 323, 646, 1292, 2584, 37, 113, 4181, 15, 33, 41, 123, 165, 205, 451, 615, 1353, 2255, 6765, 26
Offset: 2
Examples
Fibonacci(9) = 34; and the divisors of 34 are 1, 2, 17 and 34. Of these divisors, 1 and 2 occur earlier in the array. So the 9th row of the array is [17, 34].
Links
- Michael De Vlieger, Table of n, a(n) for n = 2..12333 (rows 2 <= n <= 100)
Programs
-
Mathematica
f[t_] := Append[t, Select[Divisors[Fibonacci[Length[t] + 1]], FreeQ[Flatten[t], # ] &]]; Flatten@Nest[f, {}, 20] (* Ray Chandler, Jun 14 2006 *) DeleteDuplicates[Flatten[Divisors[Fibonacci[Range[30]]]]] (* Harvey P. Dale, Apr 13 2020 *)
Extensions
Extended by Ray Chandler, Jun 14 2006
Comments