A229139 - OEIS

A229139

Smallest m such that Fibonacci(2n-1) = m^2 + k^2.

0, 1, 1, 2, 3, 5, 8, 9, 21, 34, 55, 89, 73, 13, 377, 610, 987, 64, 244, 4155, 4554, 10946, 2191, 28657, 15857, 74957, 34022, 29811, 50481, 134104, 832040, 162589, 387938, 711703, 1556305, 6229800, 4173137, 4059539, 1972951, 51797450, 4866315, 165580141, 46049477, 202620393, 348451533, 181781990

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OFFSET

1,4

COMMENTS

Every odd-indexed Fibonacci number (A000045) is a sum of two squares (see A124134).

Which of the a(n) are not Fibonacci numbers?

LINKS

Table of n, a(n) for n=1..46.

EXAMPLE

A000045(2*6-1) = 89 = 5^2 + 8^2 so a(6)=5.

A000045(2*8-1) = 610 = 9^2 + 23^2 = 13^2 + 21^2, so a(8)=9.

PROG