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A048500
a(n) = 2^(n-1)*(7*n-12)+7.
1
1, 2, 11, 43, 135, 375, 967, 2375, 5639, 13063, 29703, 66567, 147463, 323591, 704519, 1523719, 3276807, 7012359, 14942215, 31719431, 67108871, 141557767, 297795591, 624951303, 1308622855, 2734686215, 5704253447, 11878268935, 24696061959, 51271172103
OFFSET
0,2
FORMULA
a(n) = T(6, n), array T given by A048494.
a(0)=1, a(1)=2, a(2)=11, a(n) = 5*a(n-1)-8*a(n-2)+4*a(n-3). - Harvey P. Dale and Vincenzo Librandi, Sep 23 2011
G.f.: (1-3*x+9*x^2) / ((1-x)*(1-2*x)^2). - Colin Barker, Aug 24 2016
PROG
(Magma) [2^(n-1)*(7*n-12)+7: n in [0..30]]; // Vincenzo Librandi, Sep 23 2011
(PARI) Vec((1-3*x+9*x^2)/((1-x)*(1-2*x)^2) + O(x^40)) \\ Colin Barker, Aug 24 2016
CROSSREFS
Cf. A048494.
Sequence in context: A140322 A027247 A141190 * A197189 A050620 A027253
KEYWORD
nonn,easy
EXTENSIONS
Formula from Ralf Stephan, Jan 15 2004
STATUS
approved