A117809 a(n,m) =Floor[N[(-2 + Sqrt[3])^n + (-2 - Sqrt[3])^n]/2^m].

-2, 7, 3, -26, -13, -7, 96, 48, 24, 12, -362, -181, -91, -46, -23, 1350, 675, 337, 168, 84, 42, -5042, -2521, -1261, -631, -316, -158, -79, 18816, 9408, 4704, 2352, 1176, 588, 294, 147, -70226, -35113, -17557, -8779, -4390, -2195, -1098, -549, -275, 262086, 131043, 65521, 32760, 16380, 8190, 4095

Offset

0,1

Comments

A triangular prime alternating sign Binet like function.

Links

Table of n, a(n) for n=0..51.

Example

-2
7, 3
-26, -13,-7
96, 48, 24, 12
-362,-181, -91, -46, -23
1350, 675, 337, 168, 84, 42

Mathematica

f[n_, m_] = N[(-2 + Sqrt[3])^n + (-2 - Sqrt[3])^n]/2^m a = Table[Table[Floor[f[n, m]], {m, 1, n}], {n, 1, 10}] aa = Flatten[a] pp = Flatten[Table[If[PrimeQ[aa[[n]]], aa[[n]], {}], {n, 1, Length[aa]}]] Length[pp]/Length[aa]

Crossrefs

Sequence in context: A089124 A210662 A229610 * A052091 A090276 A249782

Adjacent sequences: A117806 A117807 A117808 * A117810 A117811 A117812

Keyword

sign,tabl

Author

Roger L. Bagula, Apr 29 2006

Status

approved