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Search: id:A064989
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| A064989 |
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Multiplicative with a(2^e)=1 and a(p^e)=prevprime(p)^e for odd primes p. |
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+0
2
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| 1, 1, 2, 1, 3, 2, 5, 1, 4, 3, 7, 2, 11, 5, 6, 1, 13, 4, 17, 3, 10, 7, 19, 2, 9, 11, 8, 5, 23, 6, 29, 1, 14, 13, 15, 4, 31, 17, 22, 3, 37, 10, 41, 7, 12, 19, 43, 2, 25, 9, 26, 11, 47, 8, 21, 5, 34, 23, 53, 6, 59, 29, 20, 1, 33, 14, 61, 13, 38, 15, 67, 4, 71, 31, 18, 17, 35, 22, 73, 3, 16
(list; graph; listen)
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OFFSET
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1,3
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,1000
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EXAMPLE
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a(20)=a(2^2*5)=a(2^2)*a(5)=prevprime(5)=3.
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PROGRAM
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(PARI) { for (n=1, 1000, f=factor(n)~; a=1; j=1; if (n>1 && f[1, 1]==2, j=2); for (i=j, length(f), a*=precprime(f[1, i] - 1)^f[2, i]); write("b064989.txt", n, " ", a) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 02 2009]
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CROSSREFS
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Cf. A003961.
Sequence in context: A117364 A120250 A116529 this_sequence A030067 A105800 A105602
Adjacent sequences: A064986 A064987 A064988 this_sequence A064990 A064991 A064992
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KEYWORD
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mult,nonn
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AUTHOR
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Vladeta Jovovic (vladeta(AT)eunet.rs), Oct 30 2001
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