olymmath

Putnam 2013 B1

  • Session B

For positive integers nn, let the numbers c(n)c(n) be determined by the rules c(1)=1c(1) = 1, c(2n)=c(n)c(2n) = c(n), and c(2n+1)=(−1)nc(n)c(2n+1) = (-1)^n c(n). Find the value of ∑n=12013c(n)c(n+2).\sum_{n=1}^{2013} c(n) c(n+2).

Curated text Kedlaya Putnam archive. Quoted with source.

Solutions

Human solution Solution 1 by Kiran Kedlaya and Lenny Ng

The terms of the source let olymmath link to this solution but not copy it. Read the solution (Kedlaya Putnam archive).

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