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A161225
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a(n) = number of distinct integers that can be constructed by removing one or more 0's from the binary representation of n, and concatenating while leaving the remaining digits in their same order.
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0
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0, 1, 0, 2, 1, 1, 0, 3, 2, 3, 1, 2, 1, 1, 0, 4, 3, 5, 2, 5, 3, 3, 1, 3, 2, 3, 1, 2, 1, 1, 0, 5, 4, 7, 3, 8, 5, 5, 2, 7, 5, 7, 3, 5, 3, 3, 1, 4, 3, 5, 2, 5, 3, 3, 1, 3, 2, 3, 1, 2, 1, 1, 0, 6, 5, 9, 4, 11, 7, 7, 3, 11, 8, 11, 5, 8, 5, 5, 2, 9, 7, 11, 5, 11, 7, 7, 3, 7, 5, 7, 3, 5, 3, 3, 1, 5, 4, 7, 3, 8, 5, 5, 2
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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EXAMPLE
| 20 in binary is 10100. By removing one, two, or three 0's from this, we can come up with these distinct integers written in binary: 1100, 1010, 110, 101, 11. There are five of these, so a(20) = 5.
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PROG
| (MAGMA) ndi:=function(n) a:=Intseq(n, 2); p:=1; c:=1; for j:=1 to #a do if a[j] eq 0 then c+:=1; else p*:=c; c:=1; end if; end for; return p-1; end function; [ ndi(n): n in [1..103] ]; [From Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jun 10 2009]
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CROSSREFS
| Cf. A007088 (numbers written in base 2). [From Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jun 10 2009]
Sequence in context: A023416 A080791 A124748 * A174980 A119513 A085815
Adjacent sequences: A161222 A161223 A161224 * A161226 A161227 A161228
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KEYWORD
| base,nonn
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AUTHOR
| Leroy Quet, Jun 06 2009
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EXTENSIONS
| Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jun 09 2009
More terms from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jun 10 2009
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