A305378 Tribonacci representation of 2n+1, written in base 10.

1, 3, 5, 8, 10, 12, 16, 18, 20, 22, 25, 27, 33, 35, 37, 40, 42, 44, 48, 50, 52, 54, 65, 67, 69, 72, 74, 76, 80, 82, 84, 86, 89, 91, 97, 99, 101, 104, 106, 108, 128, 130, 132, 134, 137, 139, 141, 145, 147, 149, 152, 154, 160, 162, 164, 166, 169, 171, 173, 177, 179, 181, 192, 194, 196, 198, 201

Offset: 0

Author

N. J. A. Sloane, Jun 12 2018

Keywords

• nonn
• base

Links

• Robert Israel, Table of n, a(n) for n = 0..10000

Crossrefs

Equals A003726(2n+1).

Cf. A278038.

Programs

Maple

L[0]:= [0]: L[1]:= [1]:
for d from 2 to 10 do
  L[d]:= map(t -> (2*t, `if`(t mod 4 <> 3, 2*t+1,NULL)), L[d-1])
od:
A003726:=map(op,[seq(L[i],i=0..10)]):
seq(A003726[i],i=2..nops(A003726),2); # Robert Israel, Jun 12 2018

Python

def A305378(n):
    m, tlist, s = 2*n+1, [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

Extensions

More terms from Robert Israel, Jun 12 2018