How many associative binary operations are there on a 2 element set?
64658
How many associative binary operations for a set of two elements?
109219
How do the sets $\emptyset\times B,\ A\ \times \emptyset, \ \emptyset \times \emptyset $ look like?
32081
The dual version of trichotomy of cardinality without AC
120744
How many $n\times m$ binary matrices are there, up to row and column permutations?
74839
Catalan numbers: bijection between applications of a binary operator and Dyck words.
158580
Permutation count of AABBC
20174
Discrete mathematics bit strings
28687
Efficient bitwise operations for counting bits or find the right|left most ones
143074
Finding cartesian product with PHP associative arrays
85852
How many total order relations on a set $A$?
102595
Number of ones in Binary matrix multiplication
61602
Binary strings (words) proof
114752
Number of permutations of a specific cycle decomposition
36612
Strange set notation (a set as a power of 2)?
36254
how many semantically different boolean functions are there for n boolean variables?
104056
Finding element in binary representation of $GF(2^6)$
26262
Is there an easy way to see associativity or non-associativity from an operation's table?