28440

Appears in sequences

• McKay-Thompson series of class 16A for Monster.at n=19A058514
• a(0)=360, a(n)=a(n-1)+720 for n>=1.at n=39A140801
• Nine times hexagonal numbers: a(n) = 9*n*(2*n-1).at n=40A152994
• Triangle read by rows: T(n,m)=A060187(1+n,1+m) *n! / (n-m)!at n=19A177429
• Half the number of nX4 binary arrays with the number of 1-1 horizontal, vertical, diagonal and antidiagonal adjacencies equal to the number of 0-0 adjacencies.at n=4A183285
• Half the number of n X 5 binary arrays with the number of 1-1 horizontal, vertical, diagonal and antidiagonal adjacencies equal to the number of 0-0 adjacencies.at n=3A183286
• T(n,k) = Half the number of n X k binary arrays with the number of 1-1 horizontal, vertical, diagonal and antidiagonal adjacencies equal to the number of 0-0 adjacencies.at n=31A183289
• T(n,k) = Half the number of n X k binary arrays with the number of 1-1 horizontal, vertical, diagonal and antidiagonal adjacencies equal to the number of 0-0 adjacencies.at n=32A183289
• Number of arrangements of n+1 nonzero numbers x(i) in -2..2 with the sum of trunc(x(i)/x(i+1)) equal to zero.at n=7A189538
• T(n,k)=Number of arrangements of n+1 nonzero numbers x(i) in -k..k with the sum of trunc(x(i)/x(i+1)) equal to zero.at n=43A189545
• Number of arrangements of 9 nonzero numbers x(i) in -n..n with the sum of trunc(x(i)/x(i+1)) equal to zero.at n=1A189552
• Number of nXnXn triangular 0..3 arrays with some element plus some adjacent element totalling 3+1, 3 or 3-1 exactly once.at n=5A270845
• T(n,k)=Number of nXnXn triangular 0..k arrays with some element plus some adjacent element totalling k+1, k or k-1 exactly once.at n=33A270850
• Number of 6 X 6 X 6 triangular 0..n arrays with some element plus some adjacent element totalling n+1, n or n-1 exactly once.at n=2A270855
• Triangle read by rows: T(n,m) is the number of inequivalent n X m matrices under action of the Klein group, with one-fifth of 1s, 2s, 3s, 4s and 5s (ordered occurrences rounded up/down if n*m != 0 mod 5).at n=17A287021
• a(1) = 1; a(n+1) = Sum_{d|n} sigma(n/d)*a(d), where sigma = sum of divisors (A000203).at n=38A307817
• a(n) = 1*2*3*4*5*6*7*8 - 9*10*11*12*13*14*15*16 + 17*18*19*20*21*22*23*24 - ... + (up to n).at n=11A319549
• Solutions k of the equation isigma(k) = isigma(k-1) + isigma(k-2) where isigma(k) is the sum of the infinitary divisors of k (A049417).at n=4A332975
• Number of permutations of [n] such that the number of cycles of length k is zero or a divisor of k for every k.at n=8A374292