login
This site is supported by donations to The OEIS Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A192233 Constant term of the reduction of the n-th cyclotomic polynomial by x^2->x+1. 2
-1, 1, 2, 2, 5, 2, 13, 3, 7, 3, 89, 2, 233, 5, 8, 14, 1597, 5, 4181, 10, 47, 23, 28657, 12, 4596, 57, 1619, 65, 514229, 16, 1346269, 611, 2102, 379, 12461, 85, 24157817, 989, 14357, 533, 165580141, 113, 433494437, 3026, 22201, 6767, 2971215073, 598, 171486453, 3836 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

See A192232.

LINKS

Table of n, a(n) for n=1..50.

MATHEMATICA

q[x_] := x + 1;

reductionRules = {x^y_?EvenQ -> q[x]^(y/2),

   x^y_?OddQ -> x q[x]^((y - 1)/2)};

t = Table[

   Last[Most[

     FixedPointList[Expand[#1 /. reductionRules] &,

      Cyclotomic[n, x]]]], {n, 1, 50}];

Table[Coefficient[Part[t, n], x, 0], {n, 1, 50}]  (* A192233 *)

Table[Coefficient[Part[t, n], x, 1], {n, 1,

  50}]  (* A051258 Fibocyclotomic numbers *)

(* by Peter J. C. Moses, Jun 25 2011 *)

CROSSREFS

Cf. A192232.

Sequence in context: A213642 A303073 A068058 * A144943 A114976 A085483

Adjacent sequences:  A192230 A192231 A192232 * A192234 A192235 A192236

KEYWORD

sign

AUTHOR

Clark Kimberling, Jun 26 2011

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 8 18:37 EST 2019. Contains 329865 sequences. (Running on oeis4.)