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A022031
Define the sequence T(a(0),a(1)) by a(n+2) is the greatest integer such that a(n+2)/a(n+1) < a(n+1)/a(n) for n >= 0. This is T(4,17).
3
4, 17, 72, 304, 1283, 5414, 22845, 96397, 406757, 1716352, 7242319, 30559689, 128949662, 544115986, 2295951781, 9687997993, 40879475731, 172495033261, 727860031657, 3071278144467, 12959565068034, 54684179957837, 230745362360740, 973653116715681, 4108426630946045
OFFSET
0,1
COMMENTS
The empirical g.f. / recurrence agrees with the original definition for at least 2000 terms (and a(2000) ~ 10^1250). - M. F. Hasler, Feb 11 2016
LINKS
FORMULA
Empirical g.f.: -(x^6+x^5+x^4+x^3-x-4) / ((x-1)*(x^6+2*x^5+3*x^4+4*x^3+4*x^2+3*x-1)). - Colin Barker, Sep 18 2015
a(n+1) = ceiling(a(n)^2/a(n-1))-1 for all n > 0. a(n+1)/a(n) ~ 4.219599938... as n -> oo. - M. F. Hasler, Feb 11 2016
PROG
(PARI) a=[4, 17]; for(n=2, 2000, a=concat(a, ceil(a[n]^2/a[n-1])-1)); A022031(n)=a[n+1] \\ M. F. Hasler, Feb 11 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Edited by M. F. Hasler, Feb 11 2016
STATUS
approved