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A070251
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Unrelated-factorial numbers: product of numbers unrelated to n (numbers which have a common divisor with n but do not divide n).
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1
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1, 1, 1, 1, 1, 4, 1, 6, 6, 192, 1, 720, 1, 23040, 6480, 10080, 1, 12902400, 1, 34836480, 2449440, 1857945600, 1, 50295168000, 3000, 980995276800, 9797760, 9564703948800, 1, 1518492398911488000, 1, 41845579776000, 1571364748800
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,6
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COMMENTS
| a(p) = 1 if p is a prime. 4 is the only composite number such that a(4) = 1.
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FORMULA
| a(n) = A055067(n)/A001783(n). - Vladeta Jovovic (vladeta(AT)eunet.rs), May 06 2002
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MAPLE
| A070251 := proc(n) local i;
remove(k->igcd(n, k)=1, {$1..n}); numtheory[divisors](n);
mul(i, i = %% minus % ) end: # Peter Luschny, Oct 11 2011
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CROSSREFS
| Sequence in context: A021028 A193529 A066575 * A134234 A205137 A154905
Adjacent sequences: A070248 A070249 A070250 * A070252 A070253 A070254
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KEYWORD
| nonn
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), May 05 2002
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EXTENSIONS
| More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), May 06 2002
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