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A077238 Combined Diophantine Chebyshev sequences A077236 and A077235. 3
4, 5, 11, 16, 40, 59, 149, 220, 556, 821, 2075, 3064, 7744, 11435, 28901, 42676, 107860, 159269, 402539, 594400, 1502296, 2218331, 5606645, 8278924, 20924284, 30897365, 78090491, 115310536, 291437680 (list; graph; refs; listen; history; internal format)
OFFSET

0,1

COMMENTS

a(n)^2 - 3*b(n)^2 = 13, with the companion sequence b(n)= A077237(n).

LINKS

Index entries for sequences related to Chebyshev polynomials.

FORMULA

a(2*k)= A077236(k) and a(2*k+1)= A077235(k), k>=0.

G.f.: (1-x)*(4+9*x+4*x^2)/(1-4*x^2+x^4).

EXAMPLE

11 = a(2) = sqrt(3*A077237(2)^2 + 13) = sqrt(3*6^2 + 13)= sqrt(121) = 11.

CROSSREFS

Sequence in context: A066898 A118143 A001350 * A185507 A000286 A036539

Adjacent sequences:  A077235 A077236 A077237 * A077239 A077240 A077241

KEYWORD

nonn,easy

AUTHOR

Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de), Nov 08 2002

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Last modified February 16 07:10 EST 2012. Contains 205874 sequences.