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A147755 a(n) = the largest integer that, when represented in binary, occurs at least twice as a substring in the binary representation of n. 3
1, 0, 1, 1, 3, 0, 1, 2, 1, 1, 1, 3, 7, 0, 1, 2, 1, 2, 5, 2, 3, 1, 1, 2, 3, 3, 3, 7, 15, 0, 1, 2, 1, 4, 2, 2, 3, 2, 2, 10, 5, 2, 5, 3, 7, 1, 1, 2, 3, 2, 5, 6, 3, 3, 3, 3, 3, 7, 7, 15, 31, 0, 1, 2, 1, 4, 2, 2, 3, 4, 9, 2, 2, 4, 2, 3, 7, 2, 2, 2, 2, 10, 21, 5, 5, 2, 2, 5, 11, 3, 5, 7, 15, 1, 1, 2, 3, 4, 2, 6, 3, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,5

COMMENTS

The substrings (each equal to the binary representation of a(n)) may overlap in the binary representation of n.

LINKS

Alois P. Heinz, Table of n, a(n) for n = 3..8190

EXAMPLE

21 in binary is 10101. 101 (5 in decimal) occurs twice in 10101: (101)01 and 10(101). Since no larger integer (when represented in binary) occurs more than once within 10101, then a(21) = 5.

MATHEMATICA

Table[With[{d = IntegerDigits[n, 2]}, SelectFirst[Range[n, 0, -1], SequenceCount[d, IntegerDigits[#, 2], Overlaps -> True] >= 2 &]], {n, 3, 104}] (* Michael De Vlieger, Oct 30 2017 *)

CROSSREFS

Cf. A147756, A242869.

Sequence in context: A242869 A224878 A129555 * A307195 A231188 A249695

Adjacent sequences:  A147752 A147753 A147754 * A147756 A147757 A147758

KEYWORD

base,nonn,look

AUTHOR

Leroy Quet, Nov 11 2008

EXTENSIONS

Extended by Ray Chandler, Nov 14 2008

STATUS

approved

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Last modified May 23 11:20 EDT 2019. Contains 323514 sequences. (Running on oeis4.)