A047379 - OEIS

A047379

Numbers that are congruent to {0, 2, 4, 5} mod 7.

0, 2, 4, 5, 7, 9, 11, 12, 14, 16, 18, 19, 21, 23, 25, 26, 28, 30, 32, 33, 35, 37, 39, 40, 42, 44, 46, 47, 49, 51, 53, 54, 56, 58, 60, 61, 63, 65, 67, 68, 70, 72, 74, 75, 77, 79, 81, 82, 84, 86, 88, 89, 91, 93, 95, 96

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..56.

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

FORMULA

a(n) = floor(floor((7n + 2)/2)/2).

a(n) = floor((7n-5)/4). - Gary Detlefs, Mar 07 2010

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

From Wesley Ivan Hurt, Dec 03 2014: (Start)

a(n) = a(n-1) + a(n-4) - a(n-5), n>5;

a(n) = (14*n-13-(-1)^n+2*i^n*(-1)^((3+(-1)^n)/4))/8, where i = sqrt(-1);

a(n) = A047215(n-1) - A057353(n-1). (End)

MAPLE

A047379:=n->floor((7*n-5)/4): seq(A047379(n), n=1..100); # Wesley Ivan Hurt, Dec 03 2014

MATHEMATICA

Select[Range[0, 100], MemberQ[{0, 2, 4, 5}, Mod[#, 7]]&] (* Harvey P. Dale, Apr 10 2014 *)

PROG

(Magma) [Floor((7*n-5)/4) : n in [1..100]]; // Wesley Ivan Hurt, Dec 03 2014

CROSSREFS

Cf. A047215, A057353.

Sequence in context: A169581 A184858 A083026 * A093848 A049039 A325101

Adjacent sequences: A047376 A047377 A047378 * A047380 A047381 A047382

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved