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A174934
a(n) = Sum_{k<=n} A007955(k) * A000027(n-k+1) = Sum_{k<=n} A007955(k) * (n-k+1), where A007955(m) = product of divisors of m.
0
1, 4, 10, 24, 43, 98, 160, 286, 439, 692, 956, 2948, 4953, 7154, 9580, 13030, 16497, 25796, 35114, 52432, 70191, 88434, 106700, 456742, 806909, 1157752, 1509324, 1882848, 2256401, 3439954, 4623538, 5839890, 7057331, 8275928, 9495750, 20793268, 32090823, 43389822
OFFSET
1,2
EXAMPLE
For n = 4, A007955(n) = b(n): a(4) = b(1)*4 + b(2)*3 + b(3)* 2 + b(4)*1 = 1*4 + 2*3 + 3*2 + 8*1 = 24.
MATHEMATICA
a[n_] := Sum[k^(DivisorSigma[0, k]/2) * (n-k+1), {k, 1, n}]; Array[a, 50] (* Amiram Eldar, Aug 06 2024 *)
CROSSREFS
Sequence in context: A274019 A008258 A008251 * A083168 A143696 A058514
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Apr 02 2010
EXTENSIONS
More terms from Amiram Eldar, Aug 06 2024
STATUS
approved