A047894 -id:A047894 - cp's OEIS frontend

A047893 Number of decimal digits of Euler (Zig) numbers A000364.

1, 1, 2, 4, 5, 7, 9, 11, 13, 15, 17, 20, 22, 25, 27, 30, 32, 35, 38, 41, 44, 46, 49, 52, 55, 58, 61, 64, 68, 71, 74, 77, 80, 84, 87, 90, 94, 97, 100, 104, 107, 111, 114, 118, 121, 125, 128, 132, 135, 139, 143, 146, 150, 154, 157, 161, 165, 168, 172, 176, 180, 183

Offset: 1

Labos Elemer

			a(4) = floor(log_10(1385)) + 1 = 4, E(4) = 1385, the 4th Euler number.

J. Peters and J. Stein, Mathematische Tafeln, Revised Russian Edition, Moscow, 1968.

Amiram Eldar, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Euler Number.

Cf. A000364, A034971, A034972, A000182 (tangent numbers), A047894.

a[n_] := IntegerLength[EulerE[2*n]]; Array[a, 100] (* Amiram Eldar, Mar 20 2025 *)

a(n) = #Str(subst(bernpol(2*n+1), 'x, 1/4)*4^(2*n+1)*(-1)^(n+1)/(2*n+1));

a(n) = A055642(A000364(n)) = floor(log_10(|E(2n)|)) + 1 for n >=2, where E is Euler's E function.

a(1) corrected by Amiram Eldar, Mar 20 2025

A047895 Difference of decimal orders of Euler and Tangential numbers: deviations of Zigs and Zags.

Original entry on oeis.org

0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 1, 1, 2, 2, 1, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2

Offset: 1

Labos Elemer

nonn

Peters, J. and Stein, J., Matematische Tafeln. Revised Russian Edition, 1968, Moscow.

A047893-A047894.

cp's OEIS Frontend

A047893 Number of decimal digits of Euler (Zig) numbers A000364.

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