



2, 2, 10, 122, 2770, 101042, 5405530, 398721962, 38783024290, 4809759350882, 740742376475050, 138697748786275802, 31029068327114173810, 8174145018586247784722
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OFFSET

0,1


LINKS

Table of n, a(n) for n=0..13.
G. Almkvist, Many correct digits of Pi, revisited, Amer. Math. Monthly, 104 (1997), 351353.
J. M. Borwein, Adventures with the OEIS: Five sequences Tony may like, Guttman 70th [Birthday] Meeting, 2015, revised May 2016.
J. M. Borwein, Adventures with the OEIS: Five sequences Tony may like, Guttman 70th [Birthday] Meeting, 2015, revised May 2016. [Cached copy, with permission]


FORMULA

E.g.f.: 2  2/Q(0), where Q(k)= 1  (2*k+1)*(2*k+2)/x + 1/x*(2*k+1)*(2*k+2)/Q(k+1); (continued fraction).  Sergei N. Gladkovskii, May 01 2013


CROSSREFS

Sequence in context: A005613 A005616 A005617 * A069240 A000371 A081088
Adjacent sequences: A011245 A011246 A011247 * A011249 A011250 A011251


KEYWORD

nonn


AUTHOR

N. J. A. Sloane.


STATUS

approved



