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A187917 a(n) = (1/4)*(5*(n-1)*P(n)+n*P(n-1)) where P() are the Pell numbers A000129. 0
0, 3, 14, 50, 160, 481, 1390, 3908, 10768, 29215, 78302, 207798, 546960, 1429821, 3715870, 9608200, 24734816, 63429563, 162099950, 412993210, 1049319872, 2659463705, 6725142286, 16971369036, 42748016880, 107489296599, 269850534206, 676460107070, 1693434156592, 4233924978805 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
REFERENCES
R. P. Grimaldi, Ternary strings with no consecutive 0's and no consecutive 1's, Congressus Numerantium, 205 (2011), 129-149. (The sequence desc_n.)
LINKS
FORMULA
G.f.: x^2*(2*x+3) / (x^2+2*x-1)^2. - Colin Barker, Jul 25 2013
CROSSREFS
Cf. A000129.
Sequence in context: A337075 A261043 A063025 * A164304 A098521 A084150
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Mar 15 2011
STATUS
approved

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Last modified March 18 22:56 EDT 2024. Contains 370952 sequences. (Running on oeis4.)