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A077247 Combined Diophantine Chebyshev sequences A077245 and A077243. 1
1, 2, 10, 17, 79, 134, 622, 1055, 4897, 8306, 38554, 65393, 303535, 514838, 2389726, 4053311, 18814273, 31911650, 148124458, 251239889, 1166181391, 1978007462, 9181326670, 15572819807, 72284431969, 122604550994, 569094129082 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

-5*a(n)^2 + 3*b(n)^2 = 7, with the companion sequence b(n)= A077248(n).

LINKS

Table of n, a(n) for n=0..26.

Index entries for sequences related to Chebyshev polynomials.

FORMULA

a(2*k)= A077245(k) and a(2*k+1)= A077243(k), k>=0.

G.f.: (1+x)*(1+x+x^2)/(1-8*x^2+x^4).

EXAMPLE

5*a(1)^2 + 7 = 5*4 + 7 = 27 = 3*3^2 = 3*A077248(1)^2.

CROSSREFS

Sequence in context: A214086 A127492 A258974 * A082939 A074069 A069081

Adjacent sequences:  A077244 A077245 A077246 * A077248 A077249 A077250

KEYWORD

nonn,easy

AUTHOR

Wolfdieter Lang, Nov 08 2002

STATUS

approved

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Last modified November 13 15:41 EST 2019. Contains 329106 sequences. (Running on oeis4.)