A270659 Maximal value of A270655 between indices 3^n and 3^(n+1).

1, 2, 3, 4, 7, 10, 15, 24, 34, 52, 82, 116, 180, 280, 396, 616

Offset

0,2

Links

Table of n, a(n) for n=0..15.

Maple

A270655:= proc(n) option remember;
local k;
k:= n mod 3;
if k = 0 then procname(n/3) elif k=1 then procname((n-1)/3)+procname((n+2)/3)
else procname((n+1)/3)-procname((n-2)/3)
fi
end proc:
A270655(0):= 0: A270655(1):= 1:
seq(max(map(A270655, [$3^n .. 3^(n+1)])), n=0..15); # Robert Israel, Nov 12 2018

Mathematica

b[0] = 0; b[1] = 1; b[n_] := b[n] = Switch[Mod[n, 3], 0, b[n/3], 1, b[3((n - 1)/3 + 1)] + b[n - 1], 2, b[3((n - 2)/3 + 1)] - b[n - 2]];
a[n_] := Module[{m = 1}, For[i = 3^n, i <= 3^(n + 1), i++, m = Max[m, b[i]] ]; Print[n, " ", m]; m];
a /@ Range[0, 15] (* Jean-François Alcover, Apr 10 2020 *)

Prog

(PARI) \\ here b(n) is A270655.
b(n)={if(n<2, n, my(r=n%3, q=n\3); if(r==0, b(q), if(r==1, b(q) + b(q+1), b(q+1) - b(q))))}
a(n)={my(m=1); for(i=3^n, 3^(n+1), m=max(m, b(i))); m} \\ Andrew Howroyd, Nov 11 2018

Crossrefs

Cf. A270655.

Sequence in context: A329758 A100638 A319437 * A159288 A363958 A033320

Adjacent sequences: A270656 A270657 A270658 * A270660 A270661 A270662

Keyword

nonn,more

Author

Max Barrentine, Mar 20 2016

Extensions

Offset corrected and a(12)-a(13) from Andrew Howroyd, Nov 11 2018

a(14)-a(15) from Robert Israel, Nov 12 2018

Status

approved