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URL: https://oeis.org/A355758

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A355758
Irregular triangle read by rows in which row n lists the divisors of n that are Fibonacci numbers.
0
1, 1, 2, 1, 3, 1, 2, 1, 5, 1, 2, 3, 1, 1, 2, 8, 1, 3, 1, 2, 5, 1, 1, 2, 3, 1, 13, 1, 2, 1, 3, 5, 1, 2, 8, 1, 1, 2, 3, 1, 1, 2, 5, 1, 3, 21, 1, 2, 1, 1, 2, 3, 8, 1, 5, 1, 2, 13, 1, 3, 1, 2, 1, 1, 2, 3, 5, 1, 1, 2, 8, 1, 3, 1, 2, 34, 1, 5, 1, 2, 3, 1, 1, 2, 1, 3, 13, 1, 2, 5, 8
OFFSET
1,3
EXAMPLE
Irregular triangle begins:
1;
1, 2;
1, 3;
1, 2;
1, 5;
1, 2, 3;
1;
1, 2, 8;
1, 3;
1, 2, 5;
...
MATHEMATICA
With[{fib = Fibonacci[Range[2, 10]]}, row[n_] := Select[Divisors[n], MemberQ[fib, #] &]; Table[row[n], {n, 1, fib[[-1]]}] // Flatten] (* Amiram Eldar, Jul 16 2022 *)
PROG
(PARI) isfib(n) = my(k=n^2); k+=(k+1)<<2; issquare(k) || (n>0 && issquare(k-8)); \\ A010056
row(n) = select(isfib, divisors(n));
CROSSREFS
Cf. A000012 (left border), A054494 (right border).
Cf. A005086 (row lengths), A005092 (row sums).
Subsequence of A027750.
Sequence in context: A268361 A330569 A340785 * A206778 A101872 A251659
KEYWORD
nonn,tabf
AUTHOR
Michel Marcus, Jul 16 2022
STATUS
approved