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A125687
The base 6 numbers 4 44 444 4444 44444 ... converted to base 10.
2
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
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
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