28896

Appears in sequences

• a(n) = Sum_{k=1..n-1} k^2*sigma(k)*sigma(n-k).at n=11A000477
• Numbers that, when expressed in base 4 and then interpreted in base 10, yield a multiple of the original number.at n=40A032540
• a(n) = (2*n-1)*(3*n-1)*(4*n-1).at n=11A033589
• Write the numbers from 1 to n^2 in a spiraling square; a(n) is the total of the sums of the two diagonals.at n=28A059924
• Numbers n such that sigma(n)/phi(n) is prime.at n=40A067780
• Balanced refactorable numbers.at n=6A078543
• Row sums of array A090452 (s2_{3,2}, scaled (3,2)-Stirling2).at n=5A090442
• A sequence derived from pentagonal numbers, or a Stirling number of the first kind matrix.at n=20A094952
• Numbers n such that sigma(n) = 11*phi(n) (where sigma=A000203, phi=A000010).at n=3A171257
• Triangle t(n,k) read by rows: fibonomial ratios c(n)/(c(k)*c(n-k)) where c are partial products of a generalized Fibonacci sequence with multiplier m=5.at n=30A172350
• Triangle t(n,k) read by rows: fibonomial ratios c(n)/(c(k)*c(n-k)) where c are partial products of a generalized Fibonacci sequence with multiplier m=5.at n=33A172350
• Triangle read by rows: T(n,k) = Sum_{i <= n, j <= k, (i,j) <> (n,k)} T(i,j), starting with T(1,1) = 1, for n >= 1 and 1 <= k <= n.at n=26A192933
• Values of n such that 4^n ends in n, or expomorphic numbers in base 4.at n=4A288845
• Expansion of 1/(theta_3(q) * theta_3(q^2)), where theta_3() is the Jacobi theta function.at n=28A320069
• Sequence lists numbers k > 1 such that k^2 == phi(k) (mod sigma(k)), where phi = A000010 and sigma = A000203.at n=22A324214
• Sequence lists numbers k > 1 such that k^4 == phi(k) (mod sigma(k)), where phi = A000010 and sigma = A000203.at n=6A324216
• Table read by rows, T(n, k) (for 0 <= k <= n) = (-2)^(n - k)*k!*Stirling2(n, k).at n=31A344913
• Triangle read by rows: T(n,k) (1 <= k <= n) = number of n X k Baxter matrices in which all row sums are 1.at n=48A347678