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Search: id:A087987
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| A087987 |
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a(n) is the Mertens-function value at n-th primorial number. |
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+0
2
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OFFSET
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1,3
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FORMULA
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a()=A002321[A002110(n)]
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EXAMPLE
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n=3: 3rd primoria;=30, A002321[30]=-3=a(3)
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MATHEMATICA
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q[x_] := Apply[Times, Table[Prime[i], {i, 1, x}]] s=0; i=1; Do[While[i<=q[n], s=s+MoebiusMu[i]; i++ ]; Print[s], {n, 0, 8}]//Timing
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PROGRAM
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(PARI) p=1; s=1; for(n=1, 10, pr=p; p*=prime(n); s+=sum(k=pr+1, p, moebius(k)); print1(s", ")) - Herman Jamke (hermanjamke(AT)fastmail.fm), Dec 21 2007
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CROSSREFS
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Cf. A008683, A002110, A002321, A084237.
Sequence in context: A110112 A060325 A135021 this_sequence A121412 A016561 A111382
Adjacent sequences: A087984 A087985 A087986 this_sequence A087988 A087989 A087990
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KEYWORD
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more,sign
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Oct 02 2003
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EXTENSIONS
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One more term from Herman Jamke (hermanjamke(AT)fastmail.fm), Dec 21 2007
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