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A344438
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a(n) = 1 if n can be written as a product of factorials (A000142), 0 otherwise; Characteristic function of Jordan-Polya numbers (A001013).
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2
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1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
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OFFSET
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1
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LINKS
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FORMULA
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PROG
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(PARI)
search_up_to = 120;
A076934(n) = for(k=2, oo , if(n%k, return(n), n /= k));
A001013list(lim, mx=lim)=if(lim<2, return([1])); my(v=[1], t=1); for(n=2, mx, t*=n; if(t>lim, break); v=concat(v, t*A001013list(lim\t, t))); Set(v) \\ From A001013
v001013 = A001013list(search_up_to);
A344438(n) = if(v001013[#v001013]<n, -(1/0), !!vecsearch(v001013, n));
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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