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A141060
Fourth quadrisection of Jacobsthal numbers A001045: a(n)=16a(n-1)-5.
5
3, 43, 683, 10923, 174763, 2796203, 44739243, 715827883, 11453246123, 183251937963, 2932031007403, 46912496118443, 750599937895083, 12009599006321323, 192153584101141163, 3074457345618258603, 49191317529892137643
OFFSET
0,1
COMMENTS
Jacobsthal numbers ending with the decimal digit 3. - Jianing Song, Aug 30 2022
FORMULA
a(n) = A139792(n) + A013776(n).
a(n+1) - a(n) = 10*A013709(n) = 40*A001025(n).
G.f.: (3-8*x)/((1-x)*(1-16*x)). [Colin Barker, Apr 05 2012]
a(0)=3, a(1)=43, a(n)=17*a(n-1)-16*a(n-2). - Harvey P. Dale, Mar 16 2015
From Jianing Song, Aug 30 2022: (Start)
a(n) = A001045(4*n+3).
a(n) = 10*A141032(n) + 3 = 20*A098704(n+1) + 1 = 40*A131865(n-1) + 1 for n >= 1. (End)
MATHEMATICA
LinearRecurrence[{17, -16}, {3, 43}, 30] (* Harvey P. Dale, Mar 16 2015 *)
PROG
(Magma) [(1/3)*(1+8*16^n): n in [0..25]]; // Vincenzo Librandi, May 25 2011
(PARI) a(n)=8*16^n\3+1 \\ Charles R Greathouse IV, May 25, 2011
CROSSREFS
The other quadrisections of A001045 are A195156 (first), A139792 (second), and A144864 (third).
Sequence in context: A283514 A299506 A350924 * A361878 A277496 A302218
KEYWORD
nonn,easy,less
AUTHOR
Paul Curtz, Jul 30 2008
STATUS
approved