A056891 a(n) = (s(n)-(n mod 2)) / n where s(n) is A006533.

0, 1, 1, 2, 3, 5, 8, 11, 18, 23, 35, 38, 61, 69, 98, 107, 148, 138, 213, 226, 295, 311, 396, 377, 518, 539, 663, 686, 833, 717, 1030, 1059, 1256, 1289, 1513, 1472, 1803, 1843, 2128, 2171, 2490, 2328, 2891, 2942, 3333, 3389, 3818, 3735, 4348, 4413, 4925, 4994

Offset

1,4

Links

Michael De Vlieger, Table of n, a(n) for n = 1..10000

Example

a(1) = (1-1) / 1 = 0; a(2) = (2) / 2 = 1; a(3) = (4-1) / 3 = 1; a(4) = (8) / 4 = 2; ...

Mathematica

Block[{f, g}, f[m_, n_] := Boole[Mod[n, m] == 0]; g[n_] := (n^4 - 6 n^3 + 23 n^2 - 18 n + 24)/24 + f[2, n] (-5 n^3 + 42 n^2 - 40 n - 48)/48 - f[4, n] (3 n/4) + f[6, n] (-53 n^2 + 310 n)/12 + f[12, n] (49 n/2) + f[18, n]*32 n + f[24, n]*19 n - f[30, n]*36 n - f[42, n]*50 n - f[60, n]*190 n - f[84, n]*78 n - f[90, n]*48 n - f[120, n]*78 n - f[210, n]*48 n; Array[(g[#] - Mod[#, 2])/# &, 52]] (* Michael De Vlieger, May 13 2022, after T. D. Noe at A006533 *)

Crossrefs

Cf. A006533.

Sequence in context: A000511 A263710 A135908 * A065462 A062762 A004693

Adjacent sequences: A056888 A056889 A056890 * A056892 A056893 A056894

Keyword

easy,nonn

Author

Tod A. Jebe (tjebe(AT)home.com), Sep 05 2000

Extensions

More terms from Sean A. Irvine, May 13 2022

Status

approved