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A133468
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A080814 complemented, then interpreted as binary and then re-expressed in decimal form (e.g. "1221" = "0110"). Alternately, view as A080814 with "1" mapped to "1" and "2" mapped to "0".
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1
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1, 2, 9, 150, 38505, 2523490710, 10838310072981296745, 199931532107794273605284333428918544790, 68033174967769840440887906939858451149105560803546820641877549596291376780905
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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FORMULA
| The "~" operator, as used here, represents binary inversion/complement. a(0) = 1 a(n) = a(n-1) followed by ~a(n-1)
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MATHEMATICA
| FromDigits[#, 2] & /@ NestList[ Flatten[# /. {0 -> {0, 1}, 1 -> {1, 0}}] &, {1}, 9] (* Robert G. Wilson v, Aug 16 2011 *)
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PROG
| function invert(string s) returns string { s.replace("0", "2"); s.replace("1", "0"); s.replace("2", "1"); } function f(int n) returns string { if (n==0) return "1"; return concat(f(n-1), invert(f(n-1)); //Blatant opportunity for optimization } function a(int n) returns int { return f(n).InterpretAsBinary(); }
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CROSSREFS
| Cf. A080814, A080815, A048707.
Sequence in context: A174954 A193440 A117116 * A182948 A081459 A038843
Adjacent sequences: A133465 A133466 A133467 * A133469 A133470 A133471
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KEYWORD
| nonn
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AUTHOR
| Dan Reif (integer-sequences(AT)angelfaq.com), Nov 28 2007, corrected Nov 30 2007
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