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
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
More terms from Jeffrey Shallit
More terms from R. J. Mathar, Oct 22 2007
STATUS
approved