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A073670
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a(1) = 1, a(n) = the smallest composite multiple of n not included earlier such that every partial sum is prime.
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1
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1, 4, 6, 8, 10, 12, 42, 24, 72, 20, 132, 36, 52, 14, 30, 16, 68, 54, 76, 80, 126, 88, 92, 168, 150, 78, 108, 280, 290, 210, 310, 32, 198, 136, 140, 144, 222, 114, 234, 40, 410, 294, 172, 176, 90, 138, 282, 48, 784, 50, 510, 156, 424, 378, 440, 672, 342, 58, 590, 180, 366, 124, 252, 320
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OFFSET
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1,2
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COMMENTS
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LINKS
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PROG
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(PARI) earlier(v, n, k)=for(i=1, n-1, if(v[i]==k, return(k))); 0
list(lim)=my(v=vector(lim\1), s, k); s=v[1]=1; for(n=2, #v, k=n; while(isprime(k) || !isprime(s+k) || earlier(v, n, k), k+=n); s+=k; v[n]=k); v \\ Charles R Greathouse IV, Apr 24 2015
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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