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 A332784 The number of permutations of {n 1's, n 2's,...,n n's} with the property that b(1) >= b(2) >= ... >= b(n), where n k's are skipped by b(k) for k=1..n. 4
 5, 18, 110, 508, 4968, 25824, 305376, 2375616, 28316832, 202354752, 4771240704, 33499830528, 612464852736, 9023719675392, 176001733301760, 1649576855476224, 56693983168309248, 551579829498390528, 20888523161929138176, 342595860998544285696 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 LINKS Table of n, a(n) for n=2..21. FORMULA Conjecture: a(n) = A332783(n) + (n-1)!. EXAMPLE In case of n = 2. | | b(1),b(2) -----+--------------+---------- 1 | [2, 2, 1, 1] | [0, 0] 2 | [2, 1, 2, 1] | [1, 1] 3 | [1, 2, 2, 1] | [2, 0] 4 | [1, 2, 1, 2] | [1, 1] 5 | [1, 1, 2, 2] | [0, 0] In case of n = 3. | | b(1),b(2),b(3) -----+-----------------------------+--------------- 1 | [3, 3, 3, 2, 2, 2, 1, 1, 1] | [0, 0, 0] 2 | [3, 3, 3, 2, 1, 2, 1, 2, 1] | [1, 1, 0] 3 | [3, 3, 3, 1, 2, 1, 2, 1, 2] | [1, 1, 0] 4 | [3, 3, 3, 1, 1, 1, 2, 2, 2] | [0, 0, 0] 5 | [3, 2, 1, 3, 2, 1, 3, 2, 1] | [2, 2, 2] 6 | [3, 1, 2, 3, 1, 2, 3, 1, 2] | [2, 2, 2] 7 | [1, 3, 3, 3, 1, 2, 2, 2, 1] | [3, 0, 0] 8 | [2, 3, 1, 2, 3, 1, 2, 3, 1] | [2, 2, 2] 9 | [1, 3, 2, 1, 3, 2, 1, 3, 2] | [2, 2, 2] 10 | [2, 1, 3, 2, 1, 3, 2, 1, 3] | [2, 2, 2] 11 | [1, 2, 3, 1, 2, 3, 1, 2, 3] | [2, 2, 2] 12 | [2, 2, 2, 3, 3, 3, 1, 1, 1] | [0, 0, 0] 13 | [1, 1, 1, 3, 3, 3, 2, 2, 2] | [0, 0, 0] 14 | [1, 2, 2, 2, 1, 3, 3, 3, 1] | [3, 0, 0] 15 | [2, 2, 2, 1, 1, 1, 3, 3, 3] | [0, 0, 0] 16 | [2, 1, 2, 1, 2, 1, 3, 3, 3] | [1, 1, 0] 17 | [1, 2, 1, 2, 1, 2, 3, 3, 3] | [1, 1, 0] 18 | [1, 1, 1, 2, 2, 2, 3, 3, 3] | [0, 0, 0] CROSSREFS Cf. A104442, A332762, A332783, A322178, A332748, A332752, A332773. Sequence in context: A228614 A158455 A009442 * A302435 A332467 A036688 Adjacent sequences: A332781 A332782 A332783 * A332785 A332786 A332787 KEYWORD nonn AUTHOR Seiichi Manyama, Feb 23 2020 EXTENSIONS a(9)-a(17) from Bert Dobbelaere, Mar 08 2020 a(18)-a(21) from Max Alekseyev, Sep 26 2023 STATUS approved

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Last modified December 8 11:19 EST 2023. Contains 367678 sequences. (Running on oeis4.)