A072610 Values of transition of A072608(n) from alternating behavior (0,1,0,1,..) into steadily-1 (1,1,1,..) behavior or changing back. Expressing in terms of A072609(n): at n values it switches from steadily 0 into steadily 1 successive values or back.

3, 11, 29, 67, 69, 71, 179, 181, 189, 441, 1059, 2699, 6453, 6459, 6471, 15927, 40071, 40083, 40121, 100363, 251705, 251707, 251709, 251721, 251723, 251735, 251737, 251741, 251761, 637233, 637235, 637319, 637321, 637323, 637325, 637329, 637333

Offset

1,1

Comments

Values of n such that A072609(n) != A072609(n+1).

Switching zones appear in clusters of n. Remainder A004648 either drops or starts to increase at these values of n.

Links

Table of n, a(n) for n=1..37.

Example

At n=637330...637370 the change of remainder A004648 is as follows: {..637323, 4, 13, 4, 637333, 637327, 637335, 637323, 637319, 637325, 637321, 4, 11, 4, 7, 34, 29, 26, 17, 44, 43, 46, 41, 38, 49, 52, 49, 44, 37, 28, 37..}

Mathematica

mm[x_] := Mod[Mod[Prime[x], x], 2];
pm[x_] := mm[x]*mm[x+1];
Do[s1=pm[n]; s2=pm[n+1]; If[ !Equal[s1, s2], Print[n]], {n, 10^9}]

Crossrefs

Cf. A004648, A072608, A072609.

Sequence in context: A172102 A242807 A188475 * A110954 A000251 A159229

Adjacent sequences: A072607 A072608 A072609 * A072611 A072612 A072613

Keyword

nonn

Author

Labos Elemer, Jun 24 2002

Status

approved