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 A364328 Number of endofunctions on [n] such that the number of elements that are mapped to i is either 0 or a prime divisor of i. 3
 1, 0, 1, 1, 6, 21, 110, 904, 4312, 74400, 731412, 5600761, 128196024, 792051157, 18696610816, 264267572121, 7136433698464, 57948743342529, 2228312959187256, 22463157401776612, 681974906329502904, 15395459281239915282, 463374873030990445252, 6091833036158810701465 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 LINKS Alois P. Heinz, Table of n, a(n) for n = 0..444 EXAMPLE a(0) = 1: (). a(2) = 1: (22). a(3) = 1: (333). a(4) = 6: (4422), (4242), (4224), (2442), (2424), (2244). a(5) = 21: (55555), (44333), (43433), (43343), (43334), (34433), (34343), (34334), (33443), (33434), (33344), (33322), (33232), (33223), (32332), (32323), (32233), (23332), (23323), (23233), (22333). MAPLE b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0, b(n, i-1)+add( `if`(d>n, 0, b(n-d, i-1)*binomial(n, d)), d=numtheory[factorset](i)))) end: a:= n-> b(n\$2): seq(a(n), n=0..23); CROSSREFS Cf. A000040, A178682, A334370, A364327, A364344. Sequence in context: A060843 A026650 A347948 * A298837 A009253 A365880 Adjacent sequences: A364325 A364326 A364327 * A364329 A364330 A364331 KEYWORD nonn AUTHOR Alois P. Heinz, Jul 18 2023 STATUS approved

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Last modified June 17 06:37 EDT 2024. Contains 373432 sequences. (Running on oeis4.)