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A130586
Row sums of triangle A130585.
3
1, 3, 9, 19, 65, 75, 385, 531, 1545, 2115, 10241, 8283, 49153, 49539, 131145, 262675, 1048577, 788043, 4718593, 4196435, 12583305, 20981763, 92274689, 67117659, 335544385, 402702339, 1207961097, 1610662291, 7516192769, 4295100555
OFFSET
0,2
COMMENTS
A130584 row sums = A001792, the binomial transform of [1,2,3,...]: (1, 3, 8, 20, 48, 112, ...).
FORMULA
Row sums of A130585.
a(n-1) = Sum_{d|n} phi(n/d)*2^(n/d - 1). [Olivier Gérard, Jan 01 2012]
EXAMPLE
a(3) = 19 = sum of row 3 terms of A130585: (4 + 7 + 6 + 2).
MATHEMATICA
Table[Plus@@Map[Function[d, EulerPhi[(n+1)/d] 2^((n+1)/d-1)], Divisors[n+1]], {n, 0, 30}] (* Olivier Gérard, Jan 01 2012 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Gary W. Adamson, Jun 06 2007
EXTENSIONS
More terms from Olivier Gérard, Jan 01 2012
STATUS
approved