52650

Appears in sequences

• a(n) = n^2*(n^2 + 1)/2.at n=18A037270
• Maximization of sums of cubes of integer differences (b_[ i ]-i)^3 over permutations {b_[ i ], for i-1,2,...,n} on first n integers.at n=34A049031
• Tritriangular numbers: a(n) = binomial(binomial(n,2),2) = n*(n+1)*(n-1)*(n-2)/8.at n=26A050534
• Number of self-complementary 5-multigraphs on n nodes.at n=7A052108
• Smallest triangular number which is a multiple (>1) of the n-th triangular number.at n=25A068084
• Triangular numbers which are products of triangular numbers larger than 1.at n=34A068143
• Numbers k such that Sum_{d divides k} sigma(d)/phi(d) is an integer.at n=29A068991
• Triangular numbers which are 8-almost primes.at n=8A076582
• Sum of next n numbers/n if n divides the sum else n times the sum of next n numbers.at n=17A094260
• Triangular numbers whose digit reversal is a powerful(1) number (A001694).at n=4A115692
• The least number k such that there are n different representations of k as the difference of two positive triangular numbers.at n=29A136108
• A partition product of Stirling_2 type [parameter k = -5] with biggest-part statistic (triangle read by rows).at n=18A157397
• Triangular numbers whose reverse is a square (possibly with fewer digits).at n=3A179889
• Triangular numbers that are hypotenuse and a leg of a Pythagorean triple.at n=41A213188
• Triangular numbers that are the product of three distinct triangular numbers greater than 1.at n=15A225440
• Least triangular number representable as a sum of n consecutive triangular numbers, or -1 if no such triangular number exists.at n=24A238017
• Number of (n+2) X (4+2) 0..2 arrays with every consecutive three elements in every row, column, diagonal and antidiagonal having exactly two distinct values, and new values 0 upwards introduced in row major order.at n=7A252857
• Triangle read by rows: T(n, k) = S2[3,1](n, k)*k! with the Sheffer triangle S2[3,1] = (exp(x), exp(3*x) -1) given in A282629.at n=18A284861
• a(n) = lcm(sigma(n), pod(n)) / n, where sigma (k) = the sum of divisors of k (A000203) and pod(n) = the product of divisors of k (A007955).at n=44A307893
• Chessboard rectangles sequence (see Comments), also A037270 interleaved with A163102.at n=36A317714