21024

Appears in sequences

• a(1) = 7; a(n+1) = a(n)-th nonprime, where nonprimes begin at 1.at n=38A025006
• OR-convolution of squares A000290 with themselves.at n=31A033459
• Product of n with sum of next n consecutive integers.at n=23A036659
• Values of n^2 - 1 resulting from A050795.at n=12A050799
• Engel expansion of sinh(1/2).at n=36A068379
• Numbers k such that sigma(k^2-k-1) = k*(k+1).at n=27A069826
• Nonsquarefree numbers such that n-1 is prime and n+1 is square.at n=34A146980
• a(n) = 841*n - 1.at n=24A158402
• Number of (n+2) X 3 binary matrices with every 3 X 3 block having exactly four 1's.at n=5A181255
• Number of (n+2)X8 binary matrices with every 3X3 block having exactly four 1's.at n=0A181260
• T(n,k) = number of (n+2) X (k+2) binary matrices with every 3 X 3 block having exactly four 1's.at n=15A181262
• T(n,k) = number of (n+2) X (k+2) binary matrices with every 3 X 3 block having exactly four 1's.at n=20A181262
• a(n) = Pell(n)*A008655(n) for n>=1, with a(0)=1, where A008655 lists the coefficients in (theta_3(x)*theta_3(3*x)+theta_2(x)*theta_2(3*x))^4.at n=4A209448
• Array read by antidiagonals: T(m,n) = m*(m+n-1)! + Sum( n <= i <= m+n-2 ) i!at n=24A211369
• Expansion of (chi(-x) * chi(-x^3))^-3 in powers of x where chi() is a Ramanujan theta function.at n=17A229180
• a(n)=least k such that A284821(n) = A284761(k).at n=15A284822
• Square rings obtained by adding four identical cuboids from A169938, a(n) = 4*n*(n+1)*(n*(n+1)+1).at n=8A288486
• Least number k such that the determinant of the symmetric Toeplitz matrix formed by its decimal digits is equal to n.at n=30A307887
• Expansion of (theta_3(z)*theta_3(23z) + theta_2(z)*theta_2(23z))^6.at n=14A328094
• Number of partitions of n into 8 or more distinct parts.at n=43A347575