OFFSET
1,2
COMMENTS
Conjecture: for n>1, a(n) = n iff n is prime.
Companion to A156834: (1, 2, 3, 5, 5, 12, 7, 17, 19,...).
EXAMPLE
MAPLE
A156833T := proc(n, k)
end proc:
A156833 := proc(n)
add(A156833T(n, k)*k, k=1..n) ;
end proc: # R. J. Mathar, Mar 03 2013
MATHEMATICA
A054525[n_, k_] := If[Divisible[n, k], MoebiusMu[n/k], 0];
A156348[n_, k_] := Which[k < 1 || k > n, 0, Mod[n, k] == 0, Binomial[n/k - 2 + k, k - 1], True, 0];
a[n_] := Sum[T[n, k]*k, {k, 1, n}];
Table[a[n], {n, 1, 51}] (* Jean-François Alcover, Oct 15 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Gary W. Adamson, Feb 16 2009
EXTENSIONS
Extended beyond a(14) by R. J. Mathar, Mar 03 2013
STATUS
approved