A047423 - OEIS

A047423

Numbers that are congruent to {2, 3, 4, 5, 6} mod 8.

2, 3, 4, 5, 6, 10, 11, 12, 13, 14, 18, 19, 20, 21, 22, 26, 27, 28, 29, 30, 34, 35, 36, 37, 38, 42, 43, 44, 45, 46, 50, 51, 52, 53, 54, 58, 59, 60, 61, 62, 66, 67, 68, 69, 70, 74, 75, 76, 77, 78, 82, 83, 84, 85, 86, 90, 91, 92, 93, 94, 98, 99, 100, 101, 102

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..65.

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

FORMULA

a(n+1) = 3*floor(n/5) + n + 2. - Gary Detlefs, Mar 12 2010

G.f.: x*(1+x)*(2*x^4-x^3+2*x^2-x+2) / ( (x^4+x^3+x^2+x+1)*(x-1)^2 ). - R. J. Mathar, Dec 05 2011

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

a(n) = a(n-1) + a(n-5) - a(n-6) for n > 6, a(n) = a(n-5) + 8 for n > 5.

a(n) = (8*n + 2 - 3*((n+4) mod 5))/5.

a(5k) = 8k-2, a(5k-1) = 8k-3, a(5k-2) = 8k-4, a(5k-3) = 8k-5, a(5k-4) = 8k-6. (End)

MAPLE

A047423:=n->8*floor(n/5)+[(2, 3, 4, 5, 6)][(n mod 5)+1]: seq(A047423(n), n=0..100); # Wesley Ivan Hurt, Aug 03 2016

MATHEMATICA

Select[Range[0, 100], MemberQ[{2, 3, 4, 5, 6}, Mod[#, 8]] &] (* Wesley Ivan Hurt, Aug 03 2016 *)

PROG

(Magma) [n : n in [0..150] | n mod 8 in [2..6]]; // Wesley Ivan Hurt, Aug 03 2016

CROSSREFS

Sequence in context: A007093 A285469 A302706 * A032970 A137691 A215726

Adjacent sequences: A047420 A047421 A047422 * A047424 A047425 A047426

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved