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A122884
a(n+1) = 4*a(n) + 11*a(n-1) - 2*a(n-3).
4
1, 7, 39, 231, 1339, 7819, 45543, 265503, 1547347, 9018835, 52565151, 306373095, 1785671371, 10407659227, 60660275799, 353554011951, 2060663763139, 12010428632419, 70001907900303, 408001019031543, 2378004205764667
OFFSET
1,2
FORMULA
a(n+1) = 4*a(n) + 11*a(n-1) - 2*a(n-3).
G.f.: x*(1+3*x)/((2*x+1)* (1-6*x+x^2)).
MATHEMATICA
LinearRecurrence[{4, 11, -2}, {1, 7, 39}, 25] (* Paolo Xausa, Jul 19 2024 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms from Paolo P. Lava, Jul 09 2008
STATUS
approved