login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A047364 Numbers that are congruent to {3, 4, 5} mod 7. 1
3, 4, 5, 10, 11, 12, 17, 18, 19, 24, 25, 26, 31, 32, 33, 38, 39, 40, 45, 46, 47, 52, 53, 54, 59, 60, 61, 66, 67, 68, 73, 74, 75, 80, 81, 82, 87, 88, 89, 94, 95, 96, 101, 102, 103, 108, 109, 110, 115, 116, 117, 122, 123, 124, 129, 130, 131, 136, 137, 138, 143 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..3000

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

FORMULA

G.f.: x*(3+x+x^2+2*x^3)/((1+x+x^2)*(x-1)^2). - R. J. Mathar, Dec 04 2011

From Wesley Ivan Hurt, Jun 08 2016: (Start)

a(n) = a(n-1) + a(n-3) - a(n-4) for n>4.

a(n) = (21*n-6-12*cos(2*n*Pi/3)+4*sqrt(3)*sin(2*n*Pi/3))/9.

a(3k) = 7k-2, a(3k-1) = 7k-3, a(3k-2) = 7k-4. (End)

MAPLE

A047364:=n->(21*n-6-12*cos(2*n*Pi/3)+4*sqrt(3)*sin(2*n*Pi/3))/9: seq(A047364(n), n=1..100); # Wesley Ivan Hurt, Jun 08 2016

MATHEMATICA

LinearRecurrence[{1, 0, 1, -1}, {3, 4, 5, 10}, 60] (* Harvey P. Dale, Dec 03 2014 *)

Flatten[# + {3, 4, 5} & /@ (7 Range[0, 20])] (* or *)

Select[Range[0, 150], MemberQ[{3, 4, 5}, Mod[#, 7]] &] (* Robert G. Wilson v, Sep 26 2016 *)

PROG

(MAGMA) [n : n in [0..150] | n mod 7 in [3..5]]; // Wesley Ivan Hurt, Jun 08 2016

(PARI) a(n)=(n-1)\3*7 + (n-1)%3 + 3 \\ Charles R Greathouse IV, Sep 26 2016

CROSSREFS

Sequence in context: A014463 A340015 A161983 * A274519 A139445 A185345

Adjacent sequences:  A047361 A047362 A047363 * A047365 A047366 A047367

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

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 July 24 14:48 EDT 2021. Contains 346273 sequences. (Running on oeis4.)