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A074254
Composite numbers equal to the sum of the squarefree numbers from their smallest prime factor to their largest prime factor.
0
10, 21, 44, 3317, 200632, 1110101, 975558109
OFFSET
1,1
COMMENTS
The next term is greater than 4*10^9. - Robert Gerbicz, Jun 09 2007
EXAMPLE
44 = 2^2*11 = 2+3+5+6+7+10+11.
PROG
(PARI) a=vector(10^5); a[1]=1; for(n=2, 10^5, a[n]=a[n-1]+n*abs(moebius(n))); forprime(p=2, 10^5, forprime(q=p+1, 10^5, n=a[q]-a[p-1]; if((n%q==0)&&(n%p==0), k=n/(p*q); u=factor(k); w=matsize(u); if((w[1]==0)||(u[1, 1]>=p)&&(u[w[1], 1]<=q), print(n))))) - Robert Gerbicz, Jun 09 2007
CROSSREFS
Sequence in context: A086225 A240994 A014007 * A122963 A067520 A219884
KEYWORD
nonn
AUTHOR
Jason Earls, Sep 20 2002
EXTENSIONS
3 more terms from Robert Gerbicz, Jun 09 2007
STATUS
approved