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 A357570 a(n) = Sum_{k=0..floor(n/5)} (n-4*k)!/(n-5*k)!. 5
 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 9, 14, 21, 30, 41, 60, 93, 146, 225, 336, 509, 798, 1281, 2060, 3261, 5154, 8273, 13536, 22365, 36806, 60369, 99588, 166301, 280650, 474801, 802424, 1358973, 2317806, 3987185, 6893196, 11933949, 20690738, 36022161, 63107520, 111146141, 196322454, 347412753 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,6 LINKS Seiichi Manyama, Table of n, a(n) for n = 0..1000 FORMULA D-finite with recurrence a(n) = (4 * a(n-1) + n * a(n-5) + 1)/5 for n > 4. PROG (PARI) a(n) = sum(k=0, n\5, (n-4*k)!/(n-5*k)!); CROSSREFS Cf. A072374, A122852, A357532, A357533. Sequence in context: A307972 A346074 A211697 * A211676 A076299 A341015 Adjacent sequences: A357567 A357568 A357569 * A357571 A357572 A357573 KEYWORD nonn,easy AUTHOR Seiichi Manyama, Nov 19 2022 STATUS approved

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Last modified July 25 02:23 EDT 2024. Contains 374585 sequences. (Running on oeis4.)