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A344511 a(n) = Sum_{k >= 0} sign(d_k) * 2^k for any number n with decimal expansion Sum_{k >= 0} d_k * 10^k. 2
0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,11

COMMENTS

The binary expansion of a(n) encodes the nonzero digits of the decimal expansion of n.

LINKS

Rémy Sigrist, Table of n, a(n) for n = 0..8191

FORMULA

a(n) belongs to A140900 iff n belongs to A343452.

a(A007088(n)) = n.

EXAMPLE

For n = 20!:

- 2432902008176640000 is the decimal expansion of 20!, so

  1111101001111110000 is the binary expansion of a(20!),

- a(20!) = 513008.

PROG

(PARI) a(n) = fromdigits(apply(sign, digits(n)), 2)

(Python)

def a(n): return int("".join((('1' if d!='0' else '0') for d in str(n))), 2)

print([a(n) for n in range(87)]) # Michael S. Branicky, May 22 2021

CROSSREFS

Cf. A007088, A140900, A289831 (base-3 analog), A343452.

Sequence in context: A192454 A340944 A270533 * A244919 A158799 A157532

Adjacent sequences:  A344508 A344509 A344510 * A344512 A344513 A344514

KEYWORD

nonn,base

AUTHOR

Rémy Sigrist, May 21 2021

STATUS

approved

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Last modified July 27 11:04 EDT 2021. Contains 346304 sequences. (Running on oeis4.)