A068595 Number of functions from {1,2,...,n} to {1,2,...,n} such that the sum of the function values is 0 mod 3.

0, 2, 9, 85, 1041, 15552, 274514, 5592406, 129140163, 3333333333, 95103890203, 2972033482752, 100958368864084, 3704002275186006, 145964630126953125, 6148914691236517205, 275746753962112254725, 13115469358432179191808, 659473218553437863041326, 34952533333333333333333334

Offset: 1

Author

John W. Layman, Mar 13 2002

Keywords

• nonn

Comments

If the functions counted are those whose sum of values is 0 mod 2 (instead of 0 mod 3) it appears that we get A057065.

It appears that a(n) = floor((n^n)/3) for n>2.

This conjecture is false for n=8, n=14, and n=20. - Sean A. Irvine, Feb 26 2024

Links

• Sean A. Irvine, Java program (github)
• sci.math thread [Broken link?]

Crossrefs

Cf. A057065.

Extensions

a(9)-a(20) from Sean A. Irvine, Feb 26 2024