30745

Appears in sequences

• Number of n-step mappings with 4 inputs.at n=22A005945
• Distinct odd elements in 3-Pascal triangle A028262 (by row).at n=38A028268
• Odd elements (greater than 1) to right of central elements in 3-Pascal triangle A028262.at n=31A028274
• Number of nonempty subsets of {1,2,...,n} in which exactly 2/5 of the elements are <= n/3.at n=18A047199
• Number of nonempty subsets of {1,2,...,n} in which exactly 2/5 of the elements are <= (n-1)/3.at n=18A048011
• Number of nonempty subsets of {1,2,...,n} in which exactly 2/5 of the elements are <= (n+1)/3.at n=18A048044
• Partial sums of A051947.at n=9A050483
• (Terms in A029617)/2.at n=31A051432
• (Terms in A029631)/2.at n=38A051458
• Number of squares (of another matrix) in M_2(n) - the ring of 2 X 2 matrices over Z_n.at n=16A068197
• Number of compositions of n into twin primes (i.e., primes that are members of a twin prime pair, like 3, 5, 7, 11, 13, but not 2 or 23).at n=46A077608
• (Prime(prime(n))^2-1)/24.at n=33A092772
• Tenth column (m=9) of (1,4)-Pascal triangle A095666.at n=7A095819
• a(n) = C(2n-1,n) + C(2n+1,n+1) - C(0,n).at n=8A165205
• First differences of A309226: distances in A008348 from n-th low point to the next.at n=10A324783
• Number of Hamiltonian paths in an n X n square, starting from an edge, finishing anywhere, all symmetries excluded.at n=5A328931
• Odd composite integers m such that A006497(m) == 3 (mod m).at n=33A335669
• Odd composite integers m such that A085447(m) == 6 (mod m).at n=33A338078
• a(n) = Sum_{1 <= x_1, x_2, x_3 <= n} sigma( n/gcd(x_1, x_2, x_3, n) ).at n=12A373130
• a(n) = Sum_{1 <= x_1, x_2 <= n} sigma( ( n/gcd(x_1, x_2, n) )^2 ).at n=12A373132