A107681 - OEIS

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A107681

Repeat(first 2^k numbers with no 2 in ternary representation) for k>0.

3

0, 1, 0, 1, 3, 4, 0, 1, 3, 4, 9, 10, 12, 13, 0, 1, 3, 4, 9, 10, 12, 13, 27, 28, 30, 31, 36, 37, 39, 4, 0, 0, 1, 3, 4, 9, 10, 12, 13, 27, 28, 30, 31, 36, 37, 39, 40, 81, 82, 84, 85, 90, 91, 93, 94, 108, 109, 111, 112, 117, 118, 120, 121, 0, 1, 3, 4, 9, 10, 12, 13, 27, 28, 30, 31, 36, 37

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OFFSET

1,5

COMMENTS

let A032924(n) = Sum(d(i)*3^i: 0<d(i)<3, 0<=i<L)

then .... a(n) = Sum((d(i)-1)*3^i: 0<=i<L);

A032924(n) = A107680(n) + a(n);

A081604 (a(n)) <= A081604(A107680(n)) = A081604(A032924(n)) = A000523(n+1).

LINKS

Table of n, a(n) for n=1..77.

FORMULA

a(n) = A005836(A062050(n+1)).

EXAMPLE

A032924(177) = A107680(177) + a(177),

....... 1420 = ....... 1093 + 327,

.. '1221121' = ... '1111111'+ '110010',

............ = . A003462(7) + A005836(51).

CROSSREFS

Sequence in context: A061353 A016653 A096088 * A021298 A170952 A194587

Adjacent sequences: A107678 A107679 A107680 * A107682 A107683 A107684

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, May 20 2005

STATUS

approved