MathCastle
ChallengeSuperchallenge

Challenge · Superchallenge problem

Compute ∑k≡3(mod4)(28k)\displaystyle\sum_{k \equiv 3 \pmod{4}} \binom{28}{k}, the sum of (28k)\binom{28}{k} over all kk from 00 to 2828 with k≡3(mod4)k \equiv 3 \pmod{4}.

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