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A002748
Sum of logarithmic numbers.
(Formerly M0923 N0347)
2
1, 2, 3, 26, 13, 1074, -1457, 61802, 7929, 4218722, -6385349, 934344762, -5065189307, 141111736466, 235257551943, 23219206152074, -97011062913167, 11887164842925762, -91890238533000461, 4819930221202545242, -14547510704199530499, 1184314832978574919922
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)/exp(x)/x where F(x) is o.g.f. for A000203(). - Vladeta Jovovic, Feb 09 2003
MAPLE
A002748 := proc(n) local f1, f2 ; f1 := add(numtheory[sigma](i)*x^(i-1), i=1..n+1) ; f2 := add((-x)^i/i!, i=0..n+1) ; n!*coeftayl(f1*f2, x=0, n) ; end: seq(A002748(n), n=0..25) ; # R. J. Mathar, Oct 22 2007
MATHEMATICA
f1[n_] := Sum[DivisorSigma[1, i]*x^(i-1), {i, 1, n+1}]; f2[n_] := Sum[(-x)^i/i!, {i, 0, n+1}] ; a[n_] := n!*SeriesCoefficient[f1[n]*f2[n], {x, 0, n}]; Table[a[n], {n, 0, 21}] (* Jean-François Alcover, Jan 17 2014, after R. J. Mathar *)
CROSSREFS
Cf. A002750.
Sequence in context: A060371 A358390 A130975 * A056004 A032812 A099006
KEYWORD
sign,easy
EXTENSIONS
More terms from Jeffrey Shallit
More terms from R. J. Mathar, Oct 22 2007
STATUS
approved