A082802 Smallest multiple of 7 beginning with n.

14, 21, 35, 42, 56, 63, 7, 84, 91, 105, 112, 126, 133, 14, 154, 161, 175, 182, 196, 203, 21, 224, 231, 245, 252, 266, 273, 28, 294, 301, 315, 322, 336, 343, 35, 364, 371, 385, 392, 406, 413, 42, 434, 441, 455, 462, 476, 483, 49, 504, 511, 525, 532, 546, 553, 56

Offset

1,1

Links

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

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

Formula

From Colin Barker, Mar 23 2017: (Start)

G.f.: 7*x*(2 + 3*x + 5*x^2 + 6*x^3 + 8*x^4 + 9*x^5 + x^6 + 8*x^7 + 7*x^8 + 5*x^9 + 4*x^10 + 2*x^11 + x^12) / ((1 - x)^2*(1 + x + x^2 + x^3 + x^4 + x^5 + x^6)^2).

a(n) = 2*a(n-7) - a(n-14) for n>14.

(End)

Mathematica

Table[If[Mod[n, 7]==0, n, If[Mod[10 n, 7]==0, 10 n, 10 n + 7 - Mod[10 n, 7]]], {n, 56}] (* Ray Chandler, Feb 09 2014 *)

Prog

(PARI) Vec(7*x*(2 + 3*x + 5*x^2 + 6*x^3 + 8*x^4 + 9*x^5 + x^6 + 8*x^7 + 7*x^8 + 5*x^9 + 4*x^10 + 2*x^11 + x^12) / ((1 - x)^2*(1 + x + x^2 + x^3 + x^4 + x^5 + x^6)^2) + O(x^60)) \\ Colin Barker, Mar 23 2017

Crossrefs

Cf. A082799, A082800, A082801, A082803, A082804.

Sequence in context: A084995 A100466 A100467 * A258217 A272470 A094393

Adjacent sequences: A082799 A082800 A082801 * A082803 A082804 A082805

Keyword

nonn,base,easy

Author

Amarnath Murthy, Apr 20 2003

Extensions

Corrected a(3)=35 and extended by Ray Chandler, Feb 09 2014

Typo in Mathematica program fixed by Vincenzo Librandi, Feb 10 2014

Status

approved