21928

Appears in sequences

• Numbers k such that 13*4^k + 1 is prime.at n=12A002257
• Sum{T(i,n-i): i=0,1,...,n}, array T given by A047000.at n=16A047001
• Integer averages of two successive perfect powers (pp(n) + pp(n+1))/2.at n=31A075454
• a(n) = (Sum_{k=1..n} A073698(k))^(1/n).at n=40A093928
• Even numbers k such that if a person is born in year k and lives not more than 100 years, then he never celebrates his prime birthday on a prime year.at n=21A124658
• Number of isomorphism classes of nanocones with 4 pentagons and a nearsymmetric boundary of length n.at n=14A198016
• Numbers that are midway between the nearest square and the nearest cube.at n=22A233075
• Number of (n+1) X (3+1) 0..3 arrays with the minimum plus the upper median equal to the lower median plus the maximum in every 2 X 2 subblock.at n=5A235888
• Number of (n+1) X (6+1) 0..3 arrays with the minimum plus the upper median equal to the lower median plus the maximum in every 2 X 2 subblock.at n=2A235891
• T(n,k)=Number of (n+1)X(k+1) 0..3 arrays with the minimum plus the upper median equal to the lower median plus the maximum in every 2X2 subblock.at n=30A235893
• T(n,k)=Number of (n+1)X(k+1) 0..3 arrays with the minimum plus the upper median equal to the lower median plus the maximum in every 2X2 subblock.at n=33A235893
• Number of partitions of n where the difference between consecutive parts is at most 9.at n=38A238869
• Number of (n+2)X(n+2) 0..3 arrays with every 3X3 subblock row, column, diagonal and antidiagonal sum not equal to 0 3 5 6 or 7.at n=3A252193
• Number of (n+2) X (4+2) 0..3 arrays with every 3 X 3 subblock row, column, diagonal and antidiagonal sum not equal to 0 3 5 6 or 7.at n=3A252197
• T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row, column, diagonal and antidiagonal sum not equal to 0 3 5 6 or 7.at n=24A252201
• a(n) = number of steps to reach 0 when starting from k = (n^3)-1 and repeatedly applying the map that replaces k with k - A055401(k), where A055401(k) = the number of positive cubes needed to sum to k using the greedy algorithm.at n=56A261228
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 453", based on the 5-celled von Neumann neighborhood.at n=31A272275
• Number of n X 7 0..1 arrays with every element equal to 3, 4, 5, 7 or 8 king-move adjacent elements, with upper left element zero.at n=7A298956
• Number of nonequivalent binary matrices with n distinct columns and any number of distinct nonzero rows with 3 ones in every column up to permutation of rows and columns.at n=7A331716
• Numbers that are the sum of seven fifth powers in two or more ways.at n=24A345605