Student Co-author

HMC Undergraduate

Document Type



Mathematics (HMC)

Publication Date



We provide elementary combinatorial proofs of several Fibonacci and Lucas number identities left open in the book Proofs That Really Count [1], and generalize these to Gibonacci sequences Gn that satisfy the Fibonacci recurrence, but with arbitrary real initial conditions. We offer several new identities as well.

[1] A. T. Benjamin and J. J. Quinn, Proofs That Really Count: The Art of Combinatorial Proof, The Dolciani Mathematical Expositions, 27, Mathematical Association of America, Washington, DC, 2003


Previously linked to as:,452.

First published in the Electronic Journal of Combinatorics, vol. 15, no. 1 (2008).

Publisher pdf, posted with permission.

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© 2008 The Electronic Journal of Combinatorics

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