A082799 Smallest multiple of 3 beginning with n.

12, 21, 3, 42, 51, 6, 72, 81, 9, 102, 111, 12, 132, 141, 15, 162, 171, 18, 192, 201, 21, 222, 231, 24, 252, 261, 27, 282, 291, 30, 312, 321, 33, 342, 351, 36, 372, 381, 39, 402, 411, 42, 432, 441, 45, 462, 471, 48, 492, 501, 51, 522, 531, 54, 552, 561

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (0,0,2,0,0,-1).

Formula

From Colin Barker, Mar 23 2017: (Start)

G.f.: 3*x*(4 + 7*x + x^2 + 6*x^3 + 3*x^4) / ((1 - x)^2*(1 + x + x^2)^2).

a(n) = 2*a(n-3) - a(n-6) for n>6.

(End)

Mathematica

Table[If[Mod[n, 3]==0, n, 10n+3-Mod[n, 3]], {n, 56}] (* Ray Chandler, Feb 09 2014 *)
With[{m3=3*Range[1000]}, Table[SelectFirst[m3, Take[IntegerDigits[#], Min[ IntegerLength[#], IntegerLength[n]]]==IntegerDigits[n]&], {n, 60}]] (* The program uses the SelectFirst function from Mathematica version 10 *) (* Harvey P. Dale, Dec 23 2014 *)

Prog

(PARI) Vec(3*x*(4 + 7*x + x^2 + 6*x^3 + 3*x^4) / ((1 - x)^2*(1 + x + x^2)^2) + O(x^60)) \\ Colin Barker, Mar 23 2017

Crossrefs

Cf. A082800, A082801, A082802, A082803, A082804.

Sequence in context: A078600 A076638 A129939 * A089320 A227073 A116700

Adjacent sequences: A082796 A082797 A082798 * A082800 A082801 A082802

Keyword

base,easy,nonn

Author

Amarnath Murthy, Apr 20 2003

Extensions

Extended by Ray Chandler, Feb 09 2014

Status

approved