21919

Appears in sequences

• Consider all integer triples (i,j,k), j >= k > 0, with binomial(i+2,3)=j^3+k^3, ordered by increasing i; sequence gives j values.at n=18A054206
• a(n) is the smallest number k such that A073813(k) = prime(n).at n=36A073814
• a(n) is such that the a(n)-th composite number is (n-th prime)^2.at n=36A120389
• Number of days after Jan 01 1000 such that the date written in the format DDMMYYYY is palindromic.at n=19A210885
• Number of n X 2 0..2 arrays with rows, columns and antidiagonals unimodal and diagonals nondecreasing.at n=7A223927
• T(n,k)=Number of nXk 0..2 arrays with rows, columns and antidiagonals unimodal and diagonals nondecreasing.at n=37A223933
• T(n,k)=Number of nXk 0..2 arrays with rows, columns and antidiagonals unimodal and diagonals nondecreasing.at n=43A223933
• T(n,k)=Number of nXk 0..2 arrays with rows and columns unimodal and antidiagonals nondecreasing.at n=37A224057
• T(n,k)=Number of nXk 0..2 arrays with rows and columns unimodal and antidiagonals nondecreasing.at n=43A224057
• T(n,k)=Number of nXk 0..2 arrays with diagonals and rows unimodal and antidiagonals nondecreasing.at n=37A224310
• T(n,k)=Number of nXk 0..2 arrays with rows unimodal and antidiagonals nondecreasing.at n=37A224374
• Odd integers k such that for every m >= 1 the numbers k*4^m - 1 have at least three prime factors, not necessarily distinct, and k*4^m - 1 has at least two-element covering set.at n=33A233552
• Numbers k such that (26*10^k - 77)/3 is prime.at n=20A282810
• Intersection of A003052 and A283002.at n=37A283003
• Expansion of Product_{i>=1, j>=1} (1 + x^(i*(2*j - 1))).at n=39A327731
• Number of endofunctions on [n] such that the number of elements that are mapped to i is a multiple or a divisor of i.at n=6A364344