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Search: id:A063012
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| A063012 |
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Sum of distinct powers of 20; i.e. numbers with digits in {0,1) base 20; i.e. write n in base 2 and read as if written in base 20. |
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+0
2
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| 0, 1, 20, 21, 400, 401, 420, 421, 8000, 8001, 8020, 8021, 8400, 8401, 8420, 8421, 160000, 160001, 160020, 160021, 160400, 160401, 160420, 160421, 168000, 168001, 168020, 168021, 168400, 168401, 168420, 168421, 3200000, 3200001, 3200020
(list; graph; listen)
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OFFSET
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0,3
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LINKS
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Harry J. Smith, Table of n, a(n) for n=0,...,1000
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FORMULA
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a(n) = a(n-2^[log2(n)])+20^[log2(n)]. a(2n) = 20*a(n); a(2n+1) = a(2n)+1 = 20*a(n)+1.
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EXAMPLE
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a(5) = 401 since 5 written in base 2 is 101 so a(5) = 1*20^2+0*20^1+1*20^0 = 400+0+1 = 401
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PROGRAM
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(PARI) baseE(x, b)= { local(d, e, f); e=0; f=1; while (x>0, d=x-b*(x\b); x\=b; e+=d*f; f*=10); return(e) } baseI(x, b)= { local(d, e, f); e=0; f=1; while (x>0, d=x-10*(x\10); x\=10; e+=d*f; f*=b); return(e) } { for (n=0, 1000, write("b063012.txt", n, " ", baseI(baseE(n, 2), 20)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 15 2009]
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CROSSREFS
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A001477, A005836, A000695, A033042, A033043, A033044, A033045, A033046, A007088, A033047, A033048, A033049, A033050, A033051, A033052 are similar sequences for 2-16. Cf. A063013 for something similar in a different way.
Sequence in context: A041834 A063013 A028931 this_sequence A041836 A041837 A041838
Adjacent sequences: A063009 A063010 A063011 this_sequence A063013 A063014 A063015
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KEYWORD
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easy,nonn
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AUTHOR
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Henry Bottomley (se16(AT)btinternet.com), Jul 04 2001
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