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a(n) = floor(E_(n+1)/E_(n)) where E_n is n-th Euler number (see A028296 and A000364).
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%I #14 May 12 2018 14:37:46

%S 5,12,22,36,53,73,97,124,154,187,223,263,306,352,402,454,510,569,632,

%T 697,766,838,914,992,1074,1159,1248,1339,1434,1532,1634,1738,1846,

%U 1957,2071,2189,2310,2434,2561,2691,2825,2962,3102,3246,3393,3542,3696,3852

%N a(n) = floor(E_(n+1)/E_(n)) where E_n is n-th Euler number (see A028296 and A000364).

%C First nine terms are identical to those of A025740.

%D J. Peters J. and J. Stein, Mathematische Tafeln. Revised Russian Edition in 1968, Moscow, Table 9b.

%F a(n) = floor(E(n+1)/E(n)) where E(n) is the n-th coefficient in the expansion of sec(x).

%t Wolfram: ae[ x_ ] := Abs[ EulerE[ 2*x ] ] and fo[ x_ ] := Floor[ N[ ae[ x ]/ae[ x-1 ], 80 ] ]

%t Table[Floor[Abs[EulerE[2n+2]]/Abs[EulerE[2n]]],{n,60}] (* _Harvey P. Dale_, May 01 2011 *)

%Y Cf. A028296, A000364, A025740.

%K nonn,easy

%O 1,1

%A _Labos Elemer_