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A081501
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In the following triangle the n-th row begins with n and contains n-1 smallest numbers coprime to n and greater than n. Sequence gives the row sums.
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1
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1, 5, 12, 25, 35, 73, 70, 113, 129, 201, 176, 325, 247, 393, 408, 481, 425, 757, 532, 851, 789, 969, 782, 1369, 985, 1353, 1236, 1633, 1247, 2479, 1426, 1985, 1931, 2313, 2064, 3133, 2035, 2889, 2691, 3501, 2501, 4709, 2752, 3969, 3839, 4233, 3290, 5617, 3745
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OFFSET
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1,2
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COMMENTS
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1
2 3
3 4 5
4 5 7 9
5 6 7 8 9
6 7 11 13 17 19
7 8 9 10 11 12 13
8 9 11 13 15 17 19 21
For a prime p, a(p) = p*( 3p- 1)/2.
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LINKS
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PROG
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(PARI) for(k=1, 100, t=0; s=k+1; i=k+1; while(i<k+(k), if(gcd(s, k)==1, t+=s; i++); s++); print1(t+k, ", ")) - Lambert Herrgesell (zero815(AT)googlemail.com), Mar 14 2006
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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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More terms from Lambert Herrgesell (zero815(AT)googlemail.com), Mar 14 2006
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STATUS
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approved
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