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A049630
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a(n) = Sum_{i=0..floor(n/2)} T(2i,n-2i) where T is A049627.
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0
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1, 2, 4, 7, 10, 17, 22, 34, 42, 61, 72, 100, 116, 154, 176, 224, 250, 314, 348, 427, 470, 563, 612, 726, 786, 918, 988, 1141, 1220, 1399, 1492, 1694, 1802, 2030, 2148, 2404, 2534, 2820, 2968, 3284, 3444, 3796, 3976, 4361, 4562, 4979, 5192, 5654, 5890, 6389
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OFFSET
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0,2
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LINKS
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PROG
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(PARI) T(n, k) = (n+1)*(k+1) - sum(i=0, n, sum(j=0, k, gcd(i, j)>1)); \\ A049627
a(n) = sum(i=0, n\2, T(2*i, n-2*i)); \\ Michel Marcus, Aug 06 2021
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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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