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 A327645 Number of proper n-times partitions of 2n. 2
 1, 1, 6, 88, 2489, 112669, 8204101, 799422247, 109633217402, 19157475773052, 4260985739868007, 1161511740640164091, 388990633971649889649, 152369510393132343133762, 70914541309488196549283707, 38152280583855500772704976704, 23639325145221113389859164367779 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS In each step at least one part is replaced by the partition of itself into smaller parts. The parts are not resorted. LINKS Alois P. Heinz, Table of n, a(n) for n = 0..232 FORMULA a(n) = A327639(2n,n). EXAMPLE a(2) = 6: 4->31->211, 4->31->1111, 4->22->112, 4->22->211, 4->22->1111, 4->211->1111. MAPLE b:= proc(n, i, k) option remember; `if`(n=0 or k=0, 1, `if`(i>1,       b(n, i-1, k), 0) +b(i\$2, k-1)*b(n-i, min(n-i, i), k))     end: a:= n-> add(b(2*n\$2, i)*(-1)^(n-i)*binomial(n, i), i=0..n): seq(a(n), n=0..17); CROSSREFS Cf. A327639. Sequence in context: A177567 A177563 A177569 * A309165 A127183 A054952 Adjacent sequences:  A327642 A327643 A327644 * A327646 A327647 A327648 KEYWORD nonn AUTHOR Alois P. Heinz, Sep 20 2019 STATUS approved

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Last modified February 23 06:13 EST 2020. Contains 332159 sequences. (Running on oeis4.)