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A331856 a(n) is the least value obtained by partitioning the binary representation of n into consecutive blocks, and then reversing those blocks. 3
0, 1, 1, 3, 1, 3, 3, 7, 1, 3, 5, 7, 3, 7, 7, 15, 1, 3, 5, 7, 5, 11, 11, 15, 3, 7, 11, 15, 7, 15, 15, 31, 1, 3, 5, 7, 9, 11, 11, 15, 5, 11, 21, 23, 13, 23, 23, 31, 3, 7, 13, 15, 11, 23, 27, 31, 7, 15, 23, 31, 15, 31, 31, 63, 1, 3, 5, 7, 9, 11, 11, 15, 9, 19, 21 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Rémy Sigrist, Table of n, a(n) for n = 0..16384

Rémy Sigrist, PARI program for A331856

Index entries for sequences related to binary expansion of n

FORMULA

a(n)^A023416(n) = A038573(n) (where a^k denotes the k-th iterate of a).

a(n) <= n with equality iff n belongs to A000225.

EXAMPLE

For n = 6:

- the binary representation of 6 is "110",

- we can split it in 4 ways:

      "110" -> "011" -> 3

      "1" and "10" -> "1" and "01" -> 5

      "11" and "0" -> "11" and "0" -> 6

      "1" and "1" and "0" -> "1" and "1" and "0" -> 6

- we have 3 distinct values, the least being 3,

- hence a(6) = 3.

PROG

(PARI) See Links section.

CROSSREFS

See A331855 for the number of distinct values, and A331857 for the greatest value.

Cf. A000225, A023416, A038573.

Sequence in context: A246591 A173465 A151837 * A163381 A327190 A160123

Adjacent sequences:  A331853 A331854 A331855 * A331857 A331858 A331859

KEYWORD

nonn,base

AUTHOR

Rémy Sigrist, Jan 29 2020

STATUS

approved

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Last modified May 27 11:19 EDT 2022. Contains 354096 sequences. (Running on oeis4.)