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Search: id:A078641
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| A078641 |
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Numbers between 1 and n-1 coprime to n(n+1)(n+2)(n+3). |
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+0
1
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| 1, 1, 1, 1, 1, 2, 1, 2, 2, 2, 2, 2, 2, 3, 4, 5, 4, 4, 3, 4, 5, 5, 5, 6, 5, 7, 6, 6, 7, 7, 8, 6, 6, 7, 7, 10, 7, 8, 8, 9, 10, 9, 9, 10, 11, 12, 11, 11, 10, 12
(list; graph; listen)
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OFFSET
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1,6
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COMMENT
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Which integers occur? For example 19 does not.
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EXAMPLE
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a(10)=2 as only 1 and 7 are coprime to 10.11.12.13
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PROGRAM
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(PARI) newphi(v)=local(vl, fl, np); vl=length(v); np=0; for (s=1, v[1], fl=false; for (r=1, vl, if (gcd(s, v[r])>1, fl=true; break)); if (fl==false, np++)); np v=vector(4); for (i=1, 50, v[1]=i; v[2]=i+1; v[3]=i+2; v[4]=i+3; print1(newphi(v)", "))
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CROSSREFS
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Sequence in context: A029404 A029417 A029237 this_sequence A072628 A068212 A064131
Adjacent sequences: A078638 A078639 A078640 this_sequence A078642 A078643 A078644
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KEYWORD
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nonn
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AUTHOR
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Jon Perry (perry(AT)globalnet.co.uk), Dec 12 2002
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