permutations with property

asked 2017-04-03 22:41:41 +0100

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How can I get a list of permutations $\sigma \in \mathfrak{S}_n$ with the property that $\sigma(i) \geq i-1$ for all $i =1, dots, n.$

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5524 ●4 ●46 ●123

Like that

sage: n=4
sage: [sigma for sigma in Permutations(n) if all(sigma(i)>=i-1 for i in range(1,n+1))]

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Asked: 2017-04-03 22:41:41 +0100

Seen: 1,306 times

Last updated: Apr 04 '17