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A152966 Twice repdigit numbers. 1
0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 22, 44, 66, 88, 110, 132, 154, 176, 198, 222, 444, 666, 888, 1110, 1332, 1554, 1776, 1998, 2222, 4444, 6666, 8888, 11110, 13332, 15554, 17776, 19998, 22222, 44444, 66666, 88888, 111110, 133332, 155554, 177776, 199998 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,0,11,0,0,0,0,0,0,0,0,-10).

FORMULA

a(n) = A010785(n)*2.

G.f.: 2*x*(9*x^8+8*x^7+7*x^6+6*x^5+5*x^4+4*x^3+3*x^2+2*x+1) / ((x-1)*(x^2+x+1)*(x^6+x^3+1)*(10*x^9-1)). - Colin Barker, Sep 18 2013

MATHEMATICA

Join[{0}, 2*Flatten[Table[FromDigits[PadRight[{}, n, d]], {n, 5}, {d, 9}]]] (* or *) LinearRecurrence[{0, 0, 0, 0, 0, 0, 0, 0, 11, 0, 0, 0, 0, 0, 0, 0, 0, -10}, {0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 22, 44, 66, 88, 110, 132, 154, 176}, 50] (* Harvey P. Dale, Jun 20 2014 *)

CoefficientList[Series[2 x (9 x^8 + 8 x^7 + 7 x^6 + 6 x^5 + 5 x^4 + 4 x^3 + 3 x^2 + 2 x + 1)/((x - 1) (x^2 + x + 1) (x^6 + x^3 + 1) (10 x^9 - 1)), {x, 0, 40}], x] (* Vincenzo Librandi, Jun 21 2014 *)

CROSSREFS

Cf. A010785.

Sequence in context: A187350 A118070 A276128 * A066122 A119766 A030143

Adjacent sequences:  A152963 A152964 A152965 * A152967 A152968 A152969

KEYWORD

base,easy,nonn

AUTHOR

Omar E. Pol, Dec 16 2008

STATUS

approved

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Last modified December 11 12:11 EST 2017. Contains 295876 sequences.