A092274 Sum_{k=2..n} min(k,n-k)*phi(k)*(n-k).

0, 0, 0, 1, 6, 16, 38, 70, 124, 200, 314, 452, 644, 890, 1216, 1592, 2068, 2624, 3312, 4094, 5042, 6138, 7438, 8844, 10488, 12348, 14496, 16796, 19422, 22314, 25590, 29158, 33168, 37530, 42400, 47526, 53204, 59356, 66132, 73226, 81004, 89338, 98436, 108086, 118582

Offset

0,5

References

J. O'Rourke, Art Gallery Theorems and Algorithms, Oxford Univ. Press, 1987, p. 222.

Links

Table of n, a(n) for n=0..44.

Mathematica

Table[Sum[Min[k, n-k]EulerPhi[k](n-k), {k, 2, n}], {n, 0, 50}] (* Harvey P. Dale, May 02 2012 *)

Crossrefs

Sequence in context: A346375 A058272 A049712 * A068941 A130902 A300371

Adjacent sequences: A092271 A092272 A092273 * A092275 A092276 A092277

Keyword

nonn

Author

N. J. A. Sloane, Feb 17 2004

Status

approved