A379526 Number of ordered ways of writing 1 as Sum_{k=-n..n, k<>0} e(k)/k, where e(k) is 0 or 1.
1, 7, 133, 5419, 383785, 42244765, 6520970371, 1359532454017
Offset: 1
Examples
a(2) = 7 ways: {1}, {-1/2, 1, 1/2} (6 permutations).
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a(2) = 7 ways: {1}, {-1/2, 1, 1/2} (6 permutations).