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A355758 Irregular triangle read by rows in which row n lists the divisors of n that are Fibonacci numbers.

%I A355758 #10 Jul 16 2022 11:55:51
%S A355758 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,
%T A355758 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,
%U A355758 1,1,2,8,1,3,1,2,34,1,5,1,2,3,1,1,2,1,3,13,1,2,5,8
%N A355758 Irregular triangle read by rows in which row n lists the divisors of n that are Fibonacci numbers.
%e A355758 Irregular triangle begins:
%e A355758   1;
%e A355758   1, 2;
%e A355758   1, 3;
%e A355758   1, 2;
%e A355758   1, 5;
%e A355758   1, 2, 3;
%e A355758   1;
%e A355758   1, 2, 8;
%e A355758   1, 3;
%e A355758   1, 2, 5;
%e A355758   ...
%t A355758 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 *)
%o A355758 (PARI) isfib(n) = my(k=n^2); k+=(k+1)<<2; issquare(k) || (n>0 && issquare(k-8)); \\ A010056
%o A355758 row(n) = select(isfib, divisors(n));
%Y A355758 Cf. A000045, A010056.
%Y A355758 Cf. A000012 (left border), A054494 (right border).
%Y A355758 Cf. A005086 (row lengths), A005092 (row sums).
%Y A355758 Subsequence of A027750.
%K A355758 nonn,tabf
%O A355758 1,3
%A A355758 _Michel Marcus_, Jul 16 2022