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A088981 a(n+2) = a(n+1) + a(n) - [(2*n)+1] where a(0)=7, a(1)=11. 1
7, 11, 17, 25, 37, 55, 83, 127, 197, 309, 489, 779, 1247, 2003, 3225, 5201, 8397, 13567, 21931, 35463, 57357, 92781, 150097, 242835, 392887, 635675, 1028513, 1664137, 2692597, 4356679, 7049219, 11405839, 18454997 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
REFERENCES
J. Baylis and R. Haggarty, Alice in Numberland, A Student's Guide to the Enjoyment of Higher Mathematics, Macmillan Education 1988.
G. Buckwell, Mastering Mathematics, Palgrave Master Series, 2nd Ed. 1997.
R. P. C. Forman, Additional Mathematics Pure & Applied, Stanley Thornes, 1989.
LINKS
FORMULA
a(n) = [(2*(alpha^(n+3))) - (2*(beta^(n+3))) + ((2*sqrt5)*n) + (3*sqrt5)] / (sqrt5) where alpha = (1 + sqrt5) / 2 and beta = (1 - sqrt5) / 2.
MATHEMATICA
LinearRecurrence[{3, -2, -1, 1}, {7, 11, 17, 25}, 40] (* Harvey P. Dale, Jun 08 2018 *)
PROG
(PARI) a=[7, 11]; for(n=2, 10, a=concat(a, a[#a]+a[#a-1]-2*n+3)); a
CROSSREFS
Sequence in context: A046132 A162337 A056687 * A257666 A224868 A021014
KEYWORD
easy,nonn
AUTHOR
STATUS
approved

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Last modified March 28 11:59 EDT 2024. Contains 371254 sequences. (Running on oeis4.)