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A047362 Numbers that are congruent to {2, 3, 4, 5} mod 7. 1
2, 3, 4, 5, 9, 10, 11, 12, 16, 17, 18, 19, 23, 24, 25, 26, 30, 31, 32, 33, 37, 38, 39, 40, 44, 45, 46, 47, 51, 52, 53, 54, 58, 59, 60, 61, 65, 66, 67, 68, 72, 73, 74, 75, 79, 80, 81, 82, 86, 87, 88, 89, 93, 94, 95, 96, 100, 101, 102, 103, 107, 108, 109, 110 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..64.

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

FORMULA

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

From Wesley Ivan Hurt, Jun 03 2016: (Start)

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

a(n) = (14*n-7-3*(i^(2*n)+(1-i)*i^(-n)+(1+i)*i^n))/8 where i=sqrt(-1).

a(2k) = A047389(k), a(2k-1) = A047348(k). (End)

MAPLE

A047362:=n->(14*n-7-3*(I^(2*n)+(1-I)*I^(-n)+(1+I)*I^n))/8: seq(A047362(n), n=1..100); # Wesley Ivan Hurt, Jun 03 2016

MATHEMATICA

Select[Range[100], MemberQ[{2, 3, 4, 5}, Mod[#, 7]]&] (* or *) LinearRecurrence[{1, 0, 0, 1, -1}, {2, 3, 4, 5, 9}, 60] (* Harvey P. Dale, Oct 03 2015 *)

PROG

(MAGMA) [n : n in [0..150] | n mod 7 in [2, 3, 4, 5]]; // Wesley Ivan Hurt, Jun 03 2016

CROSSREFS

Cf. A047348, A047389.

Sequence in context: A158573 A194398 A047603 * A032969 A095906 A333050

Adjacent sequences:  A047359 A047360 A047361 * A047363 A047364 A047365

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified August 3 01:55 EDT 2021. Contains 346429 sequences. (Running on oeis4.)