21345

Appears in sequences

• Array read by rows in which the n-th row contains the multiples of n in increasing order using all the digits of first n numbers.at n=20A078189
• Numbers with 5 distinct digits {1,2,3,4,5} such that all adjacent digits (as well as first and last digits) are coprime.at n=12A104972
• Where record values of A119999 occur.at n=45A120001
• a(n) = Sum_{i=1..n} ((i+1)^i - 1)/i.at n=5A175151
• Permutations of 12345: Numbers having each of the decimal digits 1,...,5 exactly once, and no other digit.at n=24A178475
• Number of distinct values of Sum_{i=0..n} x(i)*binomial(n,i), where the x(i) is a vector of length n+1 that runs through all combinations of {0, 1}.at n=18A205536
• Decimal representation of permutations of lengths 1, 2, 3, ... arranged first by number of inversions and then lexicographically.at n=37A268532
• List of André permutations of the first kind.at n=14A278982
• Numbers m such that m^2+1 is semiprime with (m-1)^2+1 and (m+1)^2+1 primes.at n=37A321985
• Number of up-down permutations p of [n] such that for all i<n-1 the number of elements p(j) between p(i) and p(i+1) for j>i+1 differs from the number of elements p(k) between p(i+1) and p(i+2) for k>i+2.at n=11A367495