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A341918 Number of strong triangulations of a fixed hexagon with n interior nodes. 3
1, 15, 155, 1410, 12165, 102548, 856205, 7128420, 59386655, 495973610, 4156326090, 34965061950, 295326872685, 2504471904060, 21322339850120, 182220932483936, 1562911922345700, 13451387178653575, 116149864521206475, 1006036370555080950, 8739349976276626707, 76128234963921173340 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
a(n) = 120*(67*n^2 + 138*n + 68)*(4*n+7)!/((3*n+12)!*(n-1)!).
PROG
(PARI) a(n) = {120*(67*n^2 + 138*n + 68)*(4*n+7)!/((3*n+12)!*(n-1)!)}
CROSSREFS
Column k=3 of A341856.
Sequence in context: A323971 A006096 A346843 * A099915 A110557 A016304
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Feb 23 2021
STATUS
approved

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Last modified March 1 12:27 EST 2024. Contains 370433 sequences. (Running on oeis4.)