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A321773 Number of compositions of n into parts with distinct multiplicities and with exactly three parts. 2
1, 3, 6, 4, 9, 9, 10, 12, 15, 13, 18, 18, 19, 21, 24, 22, 27, 27, 28, 30, 33, 31, 36, 36, 37, 39, 42, 40, 45, 45, 46, 48, 51, 49, 54, 54, 55, 57, 60, 58, 63, 63, 64, 66, 69, 67, 72, 72, 73, 75, 78, 76, 81, 81, 82, 84, 87, 85, 90, 90, 91, 93, 96, 94, 99, 99 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 3..1000

FORMULA

Conjectures from Colin Barker, Dec 11 2018: (Start)

G.f.: x^3*(1 + 3*x + 5*x^2) / ((1 - x)^2*(1 + x)*(1 + x + x^2)).

a(n) = a(n-2) + a(n-3) - a(n-5) for n>7.

(End)

CROSSREFS

Column k=3 of A242887.

Sequence in context: A021278 A336761 A143940 * A083349 A065230 A316478

Adjacent sequences:  A321770 A321771 A321772 * A321774 A321775 A321776

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Nov 18 2018

STATUS

approved

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Last modified September 26 16:43 EDT 2020. Contains 337374 sequences. (Running on oeis4.)