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URL: https://oeis.org/A002750

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A002750
Sum of logarithmic numbers.
3
1, 4, 15, 76, 373, 2676, 17539, 152860, 1383561, 14658148, 143131351, 2070738924, 24754959805, 341745565396, 5260157782923, 92358395065276, 1377499388715409, 27622124789948100, 476285499100204831, 10464946811144407948, 222724531608924013701
OFFSET
0,2
REFERENCES
J. M. Gandhi, On logarithmic numbers, Math. Student, 31 (1963), 73-83.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
J. M. Gandhi, On logarithmic numbers, Math. Student, 31 (1963), 73-83. [Annotated scanned copy]
FORMULA
E.g.f.: F(x)/x*exp(x) where F(x) is o.g.f. for A000203(). a(n) = Sum_{m=1..n+1} A000203(m)*binomial(n, m-1)*(m-1)!. - Vladeta Jovovic, Feb 08 2003
MAPLE
a:= n-> n!*add(numtheory[sigma](m+1)/(n-m)!, m=0..n):
seq(a(n), n=0..22); # Alois P. Heinz, Sep 16 2021
MATHEMATICA
a[n_] := n!*Sum[DivisorSigma[1, m+1]/(n-m)!, {m, 0, n}];
Table[a[n], {n, 0, 22}] (* Jean-François Alcover, Nov 19 2024, after Alois P. Heinz *)
CROSSREFS
Cf. A000203.
Sequence in context: A032270 A198057 A263004 * A178887 A002467 A332652
KEYWORD
nonn
EXTENSIONS
More terms from Jeffrey Shallit
More terms from Vladeta Jovovic, Feb 08 2003
STATUS
approved