A173693 - OEIS

A173693

a(n) = ceiling(A107293(n)/2).

0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 5, 7, 10, 14, 20, 28, 41, 59, 85, 122, 176, 254, 367, 529, 764, 1102, 1591, 2296, 3313, 4782, 6901, 9960, 14375, 20747, 29944, 43217, 62373, 90021, 129925, 187516, 270636, 390601, 563742, 813631, 1174288, 1694813, 2446070

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OFFSET

0,9

LINKS

Table of n, a(n) for n=0..47.

FORMULA

a(n) = A107293(n) - floor(A107293(n)/2) = ceiling(A107293(n)/2).

Conjecture: a(n) = a(n-1) + a(n-2) - a(n-3) + a(n-5) + a(n-31) - a(n-32) - a(n-33) + a(n-34) - a(n-36). - R. J. Mathar, Feb 18 2016

MAPLE

A107293 := proc(n)

option remember;

if n <=4 then

op(n+1, [0, 0, 0, 0, 1]) ;

else

procname(n-1)+procname(n-2)-procname(n-3)+procname(n-5) ;

end if;

end proc:

A173693 := proc(n)

ceil(A107293(n)/2) ;

end proc: # R. J. Mathar, Feb 18 2016

MATHEMATICA

M = {{0, 1, 0, 0, 0},

{0, 0, 1, 0, 0},

{0, 0, 0, 1, 0},

{0, 0, 0, 0, 1},

{1, 0, -1, 1, 1}}

v[0] = {0, 0, 0, 0, 1}

v[n_] := v[n] = M.v[n - 1]

Table[v[n][[1]] - Floor[v[n][[1]]/2], {n, 0, 30}]

CROSSREFS

Cf. A107293.

Sequence in context: A180158 A373014 A320689 * A058278 A097333 A001083

Adjacent sequences: A173690 A173691 A173692 * A173694 A173695 A173696

KEYWORD

nonn,easy

AUTHOR

Roger L. Bagula, Nov 25 2010

STATUS

approved