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A065883 Remove factors of 4 from n (i.e. write n in base 4, drop final zeros, then rewrite in decimal). 8
1, 2, 3, 1, 5, 6, 7, 2, 9, 10, 11, 3, 13, 14, 15, 1, 17, 18, 19, 5, 21, 22, 23, 6, 25, 26, 27, 7, 29, 30, 31, 2, 33, 34, 35, 9, 37, 38, 39, 10, 41, 42, 43, 11, 45, 46, 47, 3, 49, 50, 51, 13, 53, 54, 55, 14, 57, 58, 59, 15, 61, 62, 63, 1, 65, 66, 67, 17, 69, 70, 71, 18, 73, 74, 75 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

Multiplicative with a(p^e) = if p = 2, then 2^(e%2), else p^e - Mitch Harris, Apr 19 2005.

LINKS

Harry J. Smith, Table of n, a(n) for n=1,...,1000

FORMULA

If n mod 4 = 0 then a(n) = a(n/4), otherwise a(n) = n.

Multiplicative with a(p^e) = if p = 2, then 2^(e%2), else p^e

EXAMPLE

a(7)=7, a(14)=14, a(28)=a(4*7)=7, a(56)=a(4*14)=14, a(112)=a(4^2*7)=7.

PROG

(PARI) baseA2B(x, a, b)= { local(d, e=0, f=1); while (x>0, d=x%b; x\=b; e+=d*f; f*=a); return(e) } { for (n=1, 1000, if (n%4, a=n, a=baseA2B(n, 10, 4); while (a%10 == 0, a\=10); a=baseA2B(a, 4, 10)); write("b065883.txt", n, " ", a) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Nov 03 2009]

CROSSREFS

For 2 this produces A000265, for 3 A038502 and for 10 (if n<=100) A065881.

Sequence in context: A072400 A007913 A083346 * A071975 A182659 A197701

Adjacent sequences:  A065880 A065881 A065882 * A065884 A065885 A065886

KEYWORD

base,nonn,mult

AUTHOR

Henry Bottomley (se16(AT)btinternet.com), Nov 26 2001

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Last modified February 15 05:45 EST 2012. Contains 205694 sequences.