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A176593
List of pairs n,13*n.
1
1, 13, 2, 26, 3, 39, 4, 52, 5, 65, 6, 78, 7, 91, 8, 104, 9, 117, 10, 130, 11, 143, 12, 156, 13, 169, 14, 182, 15, 195, 16, 208, 17, 221, 18, 234, 19, 247, 20, 260, 21, 273, 22, 286, 23, 299, 24, 312, 25, 325, 26, 338, 27, 351, 28, 364, 29, 377, 30, 390, 31, 403, 32, 416, 33
OFFSET
1,2
FORMULA
a(n) = (14*n+12*n*(-1)^n+1 + (-1)^(n-1))/4 for n>1.
From Colin Barker, Jan 02 2017: (Start)
a(n) = 2*a(n-2) - a(n-4) for n>4.
G.f.: x*(1+13*x) / ((1-x)^2*(1+x)^2).
(End)
MATHEMATICA
Table[{n, 13n}, {n, 50}]//Flatten (* or *) LinearRecurrence[{0, 2, 0, -1}, {1, 13, 2, 26}, 100] (* Harvey P. Dale, Oct 16 2019 *)
PROG
(PARI) Vec(x*(1+13*x) / ((1-x)^2*(1+x)^2) + O(x^30)) \\ Colin Barker, Jan 02 2017
CROSSREFS
Cf. A008595.
Sequence in context: A008832 A180704 A040168 * A031066 A154355 A078421
KEYWORD
nonn,tabf,easy
AUTHOR
Vincenzo Librandi, Apr 23 2010
EXTENSIONS
Partially edited by N. J. A. Sloane, Jun 23 2010
STATUS
approved