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A047466 Numbers that are congruent to {0, 1, 2, 4} mod 8. 2
0, 1, 2, 4, 8, 9, 10, 12, 16, 17, 18, 20, 24, 25, 26, 28, 32, 33, 34, 36, 40, 41, 42, 44, 48, 49, 50, 52, 56, 57, 58, 60, 64, 65, 66, 68, 72, 73, 74, 76, 80, 81, 82, 84, 88, 89, 90, 92, 96, 97, 98, 100, 104, 105, 106, 108, 112, 113, 114, 116, 120, 121, 122 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Bruno Berselli, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (1,0,0,1,-1).

FORMULA

G.f.: x^2*(1+x+2*x^2+4*x^3) / ( (1+x)*(1+x^2)*(1-x)^2 ). - R. J. Mathar, Oct 08 2011

a(n) = 2*n-4+(3-(-1)^n)*(1-i^(n*(n+1)))/4, where i=sqrt(-1). [Bruno Berselli, Jul 18 2012]

From Wesley Ivan Hurt, Jun 01 2016: (Start)

a(n) = a(n-1) + a(n-4) - a(n-5) for n>5.

a(2k) = A047461(k), a(2k-1) = A047467(k). (End)

MAPLE

A047466:=n->2*n-4+(3-I^(2*n))*(1-I^(n*(n+1)))/4: seq(A047466(n), n=1..100); # Wesley Ivan Hurt, Jun 01 2016

MATHEMATICA

Select[Range[0, 120], MemberQ[{0, 1, 2, 4}, Mod[#, 8]] &] (* or *) LinearRecurrence[{1, 0, 0, 1, -1}, {0, 1, 2, 4, 8}, 60] (* Bruno Berselli, Jul 18 2012 *)

PROG

Contribution from Bruno Berselli, Jul 18 2012: (Start)

(MAGMA) [n: n in [0..120] | n mod 8 in [0, 1, 2, 4]];

(Maxima) makelist(2*n-4+(3-(-1)^n)*(1-%i^(n*(n+1)))/4, n, 1, 60);

(PARI) concat(0, Vec((1+x+2*x^2+4*x^3)/((1+x)*(1+x^2)*(1-x)^2)+O(x^60))) (End)

CROSSREFS

Essentially the same as A003485.

Cf. A047461, A047467.

Sequence in context: A131625 A196000 A044952 * A003485 A072602 A049642

Adjacent sequences:  A047463 A047464 A047465 * A047467 A047468 A047469

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified May 26 17:17 EDT 2019. Contains 323597 sequences. (Running on oeis4.)