A305380 Tribonacci representation of 2^n, written in base 10.

1, 2, 4, 9, 19, 41, 88, 195, 418, 1033, 2195, 4705, 10282, 21850, 49160, 104465, 223780, 550294, 1186344, 2525345, 5514438, 11817057, 26297040, 56201282, 138856076, 295217708, 632609378, 1382640428, 2974062096, 6603081730, 14149570820, 34976354857, 74361996963

Offset

0,2

Links

Alois P. Heinz, Table of n, a(n) for n = 0..2000

Maple

T:= proc(n) T(n):= (<<0|1|0>, <0|0|1>, <1|1|1>>^n)[2, 3] end:
b:= proc(n) option remember; local j;
      if n=0 then 0
    else for j from 2 while T(j+1)<=n do od;
         b(n-T(j))+2^(j-2)
      fi
    end:
a:= n-> b(2^n):
seq(a(n), n=0..35);  # Alois P. Heinz, Jun 12 2018

Prog

(Python)
def A305380(n):
    m, tlist, s = 2**n, [1, 2, 4], 0
    while tlist[-1]+tlist[-2]+tlist[-3] <= m:
        tlist.append(tlist[-1]+tlist[-2]+tlist[-3])
    for d in tlist[::-1]:
        s *= 2
        if d <= m:
            s += 1
            m -= d
    return s # Chai Wah Wu, Jun 12 2018

Crossrefs

Equals A003726(2^n).

Cf. A000073, A278038, A305876.

Sequence in context: A141683 A142474 A078039 * A275862 A036622 A001384

Adjacent sequences: A305377 A305378 A305379 * A305381 A305382 A305383

Keyword

nonn,base

Author

N. J. A. Sloane, Jun 12 2018

Extensions

a(9)-a(24) from Robert Israel, Jun 12 2018

Terms a(25) and beyond from Alois P. Heinz, Jun 12 2018

Status

approved