A247972 Numbers k such that A247971(k+1) = A247971(k).

5, 9, 14, 19, 23, 28, 33, 37, 42, 47, 51, 56, 61, 65, 70, 75, 79, 84, 89, 93, 98, 103, 107, 112, 117, 121, 126, 131, 135, 140, 145, 149, 154, 159, 163, 168, 172, 177, 182, 186, 191, 196, 200, 205, 210, 214, 219, 224, 228, 233, 238, 242, 247, 252, 256, 261

Offset

1,1

Links

Clark Kimberling, Table of n, a(n) for n = 1..200

Mathematica

$RecursionLimit = Infinity; z = 400; v[1] = 0; v[2] = 1;
v[n_] := v[n] = v[n - 1]/(n - 2) + v[n - 2];
N[Table[2 n/v[n]^2 - Pi, {n, 2, z/4}]]
TableForm[Table[{n, N[4 n/(v[2 n]^2) - Pi], N[1/n]}, {n, 1, 10}]]
f[n_] := f[n] = Select[Range[z], 4 #/(v[2 #]^2) - Pi < 1/n &, 1];
u = Flatten[Table[f[n], {n, 1, z}]] (* A247971 *)
d = Differences[u]
v = Flatten[Position[d, 0]] (* A247972 *)

Crossrefs

Cf. A247971, A247973, A247974.

Sequence in context: A140490 A314887 A316324 * A301298 A314888 A314889

Adjacent sequences: A247969 A247970 A247971 * A247973 A247974 A247975

Keyword

nonn,easy

Author

Clark Kimberling, Sep 28 2014

Status

approved