A125687 The base 6 numbers 4 44 444 4444 44444 ... converted to base 10.

4, 28, 172, 1036, 6220, 37324, 223948, 1343692, 8062156, 48372940, 290237644, 1741425868, 10448555212, 62691331276, 376147987660, 2256887925964, 13541327555788, 81247965334732, 487487792008396, 2924926752050380, 17549560512302284, 105297363073813708

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (7,-6).

Formula

a(n) = (6^n-1)*4/5.

G.f.: 4*x/((1-x)*(1-6*x)). - Vincenzo Librandi, Sep 26 2015

Example

Base 6.........decimal
4....................4
44..................28
444................172
4444..............1036
44444.............6220
444444...........37324
4444444.........223948
44444444.......1343692
444444444......8062156
4444444444....48372940
etc.

Maple

seq((6^n-1)*4/5, n=1..24);

Mathematica

4 (6^Range[20]-1)/5  (* Harvey P. Dale, Mar 12 2011 *)
Rest[CoefficientList[Series[4 x/((1 - x) (1 - 6 x)), {x, 0, 30}], x]] (* Vincenzo Librandi, Sep 26 2015 *)
Table[FromDigits[PadRight[{}, n, 4], 6], {n, 30}] (* or *) LinearRecurrence[{7, -6}, {4, 28}, 30] (* Harvey P. Dale, Jan 02 2023 *)

Prog

(Magma) [(6^n-1)*4/5: n in [1.. 35]]; // Vincenzo Librandi, Sep 26 2015

Crossrefs

Sequence in context: A182190 A317232 A272456 * A272791 A291918 A223166

Adjacent sequences: A125684 A125685 A125686 * A125688 A125689 A125690

Keyword

easy,nonn

Author

Zerinvary Lajos, Jan 31 2007

Extensions

Edited by N. J. A. Sloane, Feb 02 2007

More terms from Vincenzo Librandi, Sep 26 2015

Status

approved