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A047392 Numbers that are congruent to {0, 1, 3, 5} mod 7. 3
0, 1, 3, 5, 7, 8, 10, 12, 14, 15, 17, 19, 21, 22, 24, 26, 28, 29, 31, 33, 35, 36, 38, 40, 42, 43, 45, 47, 49, 50, 52, 54, 56, 57, 59, 61, 63, 64, 66, 68, 70, 71, 73, 75, 77, 78, 80, 82, 84, 85, 87, 89, 91, 92, 94, 96, 98, 99, 101, 103, 105, 106, 108, 110 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

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

From Wesley Ivan Hurt, May 21 2016: (Start)

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

a(n) = (14*n - 17 - i^(2*n) + (1 + i)*i^(-n) + (1 - i)*i^n)/8.

a(2k) = A047383(k), a(2k-1) = A047355(k). (End)

a(n) = n + floor(3*n/4-3/4) - 1. - Bruno Berselli, Jun 15 2016

MAPLE

A047392:=n->(14*n-17-I^(2*n)+(1+I)*I^(-n)+(1-I)*I^n)/8: seq(A047392(n), n=1..100); # Wesley Ivan Hurt, May 21 2016

MATHEMATICA

Table[(14n-17-I^(2n)+(1+I)*I^(-n)+(1-I)*I^n)/8, {n, 80}] (* Wesley Ivan Hurt, May 21 2016 *)

Table[n + Floor[3 n/4 - 3/4] - 1, {n, 1, 70}] (* Bruno Berselli, Jun 15 2016 *)

PROG

(MAGMA) [n: n in [0..100] | n mod 7 in [0, 1, 3, 5]]; // Wesley Ivan Hurt, May 21 2016

CROSSREFS

Cf. A047355, A047383.

Cf. A047371: n + floor(3*n/4-1/2) - 1; A047379: n + floor(3*n/4-1/4) - 1.

Sequence in context: A247514 A144077 A184626 * A292648 A187330 A059546

Adjacent sequences:  A047389 A047390 A047391 * A047393 A047394 A047395

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Wesley Ivan Hurt, May 21 2016

STATUS

approved

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Last modified October 15 22:25 EDT 2019. Contains 328038 sequences. (Running on oeis4.)