21534

Appears in sequences

• Positive numbers k such that k and 2*k are anagrams in base 6 (written in base 6).at n=27A023064
• Numbers equal to a permutation (or rearrangement) of the digits of the sum of their proper divisors. Rearrangements which cause leading zeros are excluded.at n=21A085844
• a(1) = 1, a(2) = 1, a(n) = sum of tau(n) previous terms, where tau(n) is the number of divisors of n.at n=17A087549
• Number of one-element transitions among partitions of the integer n for unlabeled parts.at n=24A093695
• Triangle read by rows: T(n,k) is number of Dyck n-paths with k UUDDs, 0 <= k <= n/2.at n=38A098978
• Numbers n such that z(n) and z(n+1) are both prime, where z(n) = a^d + b^d + c^d + ..., where a*b*c* ... is the prime factorization of n and d is the largest digit of n.at n=18A109280
• First row of Modified Schroeder numbers for q=7 (A114294).at n=12A114298
• a(n) = 7 + floor((1 + Sum_{j=1..n-1} a(j))/4).at n=36A120165
• Terms in A177950 that are not in A002778.at n=41A175440
• Permutations of 12345: Numbers having each of the decimal digits 1,...,5 exactly once, and no other digit.at n=28A178475
• Number of partitions of n in which any two parts differ by at most 7.at n=46A218509
• Decimal representation of permutations of lengths 1, 2, 3, ...at n=29A306428
• Derangements of {1,2,...,n} (n >= 2) in lexicographic order.at n=13A320588