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A363328
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Total number of parts coprime to n in the partitions of n into 10 parts.
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7
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0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 10, 17, 30, 42, 64, 86, 150, 142, 300, 277, 471, 502, 970, 669, 1556, 1345, 2190, 2037, 4230, 2142, 6530, 4876, 7657, 7162, 12746, 7488, 21120, 14751, 22864, 17986, 42420, 18156, 58880, 38177, 52533, 53185, 109360, 49563, 137515, 79738
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OFFSET
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1,10
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LINKS
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FORMULA
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a(n) = Sum_{r=1..floor(n/10)} Sum_{q=r..floor((n-r)/9)} Sum_{p=q..floor((n-q-r)/8)} Sum_{o=p..floor((n-p-q-r)/7)} Sum_{m=o..floor((n-o-p-q-r)/6)} Sum_{l=m..floor((n-m-o-p-q-r)/5)} Sum_{k=l..floor((n-l-m-o-p-q-r)/4)} Sum_{j=k..floor((n-k-l-m-o-p-q-r)/3)} Sum_{i=j..floor((n-j-k-l-m-o-p-q-r)/2)} (c(i) + c(j) + c(k) + c(l) + c(m) + c(o) + c(p) + c(q) + c(r) + c(n-i-j-k-l-m-o-p-q-r)), where c(x) = [gcd(n,x) = 1] and [ ] is the Iverson bracket.
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EXAMPLE
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The partitions of 13 into 10 parts are: 1+1+1+1+1+1+1+1+1+4, 1+1+1+1+1+1+1+1+2+3, and 1+1+1+1+1+1+1+2+2+2. 13 is coprime to 1, 2, 3, and 4. Since there are 30 total parts in these partitions that are coprime to 13, a(13) = 30.
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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