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A091999 Numbers that are congruent to {2, 10} mod 12. 9
2, 10, 14, 22, 26, 34, 38, 46, 50, 58, 62, 70, 74, 82, 86, 94, 98, 106, 110, 118, 122, 130, 134, 142, 146, 154, 158, 166, 170, 178, 182, 190, 194, 202, 206, 214, 218, 226, 230, 238, 242, 250, 254, 262, 266, 274, 278, 286, 290, 298, 302, 310, 314, 322, 326, 334 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

For n > 1, a(n) = A186424(n) - A186424(n-2).

Numbers divisible by 2 but not by 3 or 4. - Robert Israel, Apr 24 2015

For n > 1, a(n) is representable as a sum of four but no fewer consecutive nonnegative integers, i.e., 10 = 1 + 2 + 3 + 4, 14 = 2 + 3 + 4 + 5, 22 = 4 + 5 + 6 + 7, etc. (see A138591) - Martin Renner, Mar 14 2016

LINKS

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

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

FORMULA

a(n) = 2*A007310(n).

a(n) = 12*(n-1)-a(n-1), with a(1)=2. [Vincenzo Librandi, Nov 16 2010]

G.f.: 2*x*(1+4*x+x^2) / ( (1+x)*(x-1)^2 ). - R. J. Mathar, Oct 08 2011

a(1)=2, a(2)=10, a(3)=14, a(n) = a(n-1)+a(n-2)-a(n-3). - Harvey P. Dale, Jun 24 2013

a(n) = 6*n-3+(-1)^n. - Wesley Ivan Hurt, Apr 23 2015

MAPLE

A091999:=n->6*n-3+(-1)^n: seq(A091999(n), n=1..100); # Wesley Ivan Hurt, Apr 23 2015

MATHEMATICA

Flatten[#+{2, 10}&/@(12*Range[0, 30])] (* or *) LinearRecurrence[{1, 1, -1}, {2, 10, 14}, 60] (* Harvey P. Dale, Jun 24 2013 *)

PROG

(Haskell)

a091999 n = a091999_list !! (n-1)

a091999_list = 2 : 10 : map (+ 12) a091999_list

-- Reinhard Zumkeller, Jan 21 2013

(MAGMA) [6*n-3+(-1)^n : n in [1..100]]; // Wesley Ivan Hurt, Apr 23 2015

CROSSREFS

Second row of A092260.

Cf. A109761 (subsequence).

Cf. A007310, A138591, A186424.

Sequence in context: A050546 A032384 A032624 * A230624 A290143 A160773

Adjacent sequences:  A091996 A091997 A091998 * A092000 A092001 A092002

KEYWORD

nonn,easy

AUTHOR

Ray Chandler, Feb 21 2004

STATUS

approved

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Last modified March 23 16:52 EDT 2019. Contains 321432 sequences. (Running on oeis4.)