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Search: id:A108672
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| A108672 |
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Sum{k=1 to n} sigma_{n-k+1}(k), where sigma_m(k) = sum{j|k} j^m. |
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+0
1
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| 1, 4, 10, 27, 73, 227, 767, 2860, 11569, 50363, 234155, 1156037, 6031747, 33130183, 190929773, 1151198266, 7243777228, 47462906925, 323188163747, 2282922216815, 16701529748617, 126359471558611, 987316752551411, 7957198067362137
(list; graph; listen)
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OFFSET
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1,2
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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EXAMPLE
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a(5) = 1^5 + (1^4 +2^4) + (1^3 +3^3) + (1^2 +2^2 +4^2) + (1^1 +5^1) =
1 + 17 + 28 + 21 + 6 = 73.
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MAPLE
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with(numtheory): s:=proc(n, k) local div: div:=divisors(n): sum(div[j]^k, j=1..tau(n)) end: a:=n->sum(s(i, n-i+1), i=1..n): seq(a(n), n=1..25); (Deutsch)
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CROSSREFS
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Sequence in context: A122744 A077923 A052982 this_sequence A000495 A027067 A050262
Adjacent sequences: A108669 A108670 A108671 this_sequence A108673 A108674 A108675
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet Jul 07 2005
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 13 2005
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