A090852 a(n) is the least positive integer such that the integer part of the arithmetic-geometric mean of a(n) and 1 is equal to n.

1, 4, 7, 10, 13, 16, 20, 24, 27, 31, 35, 39, 43, 47, 51, 55, 60, 64, 68, 73, 77, 81, 86, 90, 95, 100, 104, 109, 113, 118, 123, 127, 132, 137, 142, 146, 151, 156, 161, 166, 171, 176, 181, 186, 191, 196, 201, 206, 211, 216, 221, 226, 231, 236, 241, 246, 251, 256, 262

Offset

1,2

Links

Vaclav Kotesovec, Table of n, a(n) for n = 1..10000

Formula

floor( agm(a(n), 1) ) = n, for n>=1.

Mathematica

Table[Ceiling[y /. FindRoot[Pi/(2*EllipticK[1 - y^2]) == n, {y, 2*n}]], {n, 1, 60}] (* Vaclav Kotesovec, Sep 28 2019 *)

Crossrefs

Cf. A090853, A090854.

Sequence in context: A310681 A143456 A310682 * A182112 A090955 A310683

Adjacent sequences: A090849 A090850 A090851 * A090853 A090854 A090855

Keyword

nonn

Author

Paul D. Hanna, Dec 10 2003

Status

approved