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A270659 Maximal value of A270655 between indices 3^n and 3^(n+1). 0

%I #24 Apr 10 2020 15:15:12

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

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

%p A270655:= proc(n) option remember;

%p local k;

%p k:= n mod 3;

%p if k = 0 then procname(n/3) elif k=1 then procname((n-1)/3)+procname((n+2)/3)

%p else procname((n+1)/3)-procname((n-2)/3)

%p fi

%p end proc:

%p A270655(0):= 0: A270655(1):= 1:

%p seq(max(map(A270655,[$3^n .. 3^(n+1)])),n=0..15); # _Robert Israel_, Nov 12 2018

%t 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]];

%t a[n_] := Module[{m = 1}, For[i = 3^n, i <= 3^(n + 1), i++, m = Max[m, b[i]] ]; Print[n, " ", m]; m];

%t a /@ Range[0, 15] (* _Jean-François Alcover_, Apr 10 2020 *)

%o (PARI) \\ here b(n) is A270655.

%o 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))))}

%o a(n)={my(m=1); for(i=3^n, 3^(n+1), m=max(m, b(i))); m} \\ _Andrew Howroyd_, Nov 11 2018

%Y Cf. A270655.

%K nonn,more

%O 0,2

%A _Max Barrentine_, Mar 20 2016

%E Offset corrected and a(12)-a(13) from _Andrew Howroyd_, Nov 11 2018

%E a(14)-a(15) from _Robert Israel_, Nov 12 2018

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Last modified March 29 11:14 EDT 2024. Contains 371278 sequences. (Running on oeis4.)