OFFSET
1,1
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..100
EXAMPLE
All solutions for n=3:
..1....1....5....2....1....3....1....4....1....3....3....1....1....2....3....2
..6....3....6....6....4....6....3....5....3....5....4....4....2....5....5....3
..7....6....7....7....7....7....4....6....7....7....5....6....4....6....6....4
..
..1....1....3....1....1....1....2....4....2....4....1....2....1....1....3....2
..2....2....4....2....2....4....4....6....5....5....5....4....5....3....4....3
..6....5....7....7....3....5....6....7....7....7....6....5....7....5....6....7
..
..2....2....2
..3....3....4
..6....5....7
MATHEMATICA
T[n_, k_] := If[n == 1, k, (DivisorSum[n, EulerPhi[n/#]*(k - 1)^# &]/n + If[OddQ[n], 1 - k, k*(k - 1)^(n/2)/2])/2]; a[n_] = T[n, 7]; Array[a, 24] (* Jean-François Alcover, Nov 01 2017, after Andrew Howroyd *)
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 27 2012
EXTENSIONS
a(18)-a(24) from Andrew Howroyd, Mar 12 2017
STATUS
approved