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A019479 Define the sequence S(a_0,a_1) by a_{n+2} is the least integer such that a_{n+2}/a_{n+1}>a_{n+1}/a_n for n >= 0. This is S(4,8). 1
4, 8, 17, 37, 81, 178, 392, 864, 1905, 4201, 9265, 20434, 45068, 99400, 219233, 483533, 1066465, 2352162, 5187856, 11442176, 25236513, 55660881, 122763937, 270764386, 597189652, 1317143240, 2905050865, 6407291381, 14131726001, 31168502866, 68744297112 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Colin Barker, Table of n, a(n) for n = 0..1000

D. W. Boyd, Linear recurrence relations for some generalized Pisot sequences, Advances in Number Theory ( Kingston ON, 1991) 333-340, Oxford Sci. Publ., Oxford Univ. Press, New York, 1993.

FORMULA

Apparently satisfies a(n) = 3*a(n-1) - 2*a(n-2) + a(n-3) - a(n-4).

Empirical G.f.: (4-4*x+x^2-2*x^3)/(1-3*x+2*x^2-x^3+x^4). - Colin Barker, Feb 04 2012

PROG

(PARI) S(a0, a1, maxn) = a=vector(maxn); a[1]=a0; a[2]=a1; for(n=3, maxn, a[n]=a[n-1]^2\a[n-2]+1); a

S(4, 8, 40) \\ Colin Barker, Feb 16 2016

CROSSREFS

Sequence in context: A215108 A307545 A115618 * A084814 A098125 A296399

Adjacent sequences:  A019476 A019477 A019478 * A019480 A019481 A019482

KEYWORD

nonn

AUTHOR

R. K. Guy

STATUS

approved

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Last modified May 31 13:01 EDT 2020. Contains 334748 sequences. (Running on oeis4.)