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A105395
A simple "Fractal Jump Sequence" (FJS).
7
1, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1, 7, 1, 1
OFFSET
1,4
COMMENTS
See A105397 for definition of Fractal Jump Sequence.
a(n+2) = the digital root of the n-th centered hexagonal number (A003215). - Colin Barker, Jan 30 2015
FORMULA
a(n) = a(n-3) for n>4. - Colin Barker, Jan 30 2015
G.f.: -x*(2*x+1)*(3*x^2-x+1) / ((x-1)*(x^2+x+1)). - Colin Barker, Jan 30 2015
MATHEMATICA
PadRight[{1}, 100, {7, 1, 1}] (* Paolo Xausa, Jul 17 2024 *)
PROG
(PARI) Vec(-x*(2*x+1)*(3*x^2-x+1)/((x-1)*(x^2+x+1)) + O(x^100)) \\ Colin Barker, Jan 30 2015
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Eric Angelini, May 01 2005
STATUS
approved