49686

Appears in sequences

• Triangle of numbers of Dyck paths.at n=50A039797
• Triangle read by rows: numbers of Dyck paths.at n=49A039798
• Numbers k such that all the following properties hold: (i) k*reverse(k) is a square; (ii) k != reverse(k); (iii) k and reverse(k) are not both squares; and (iv) k and reverse(k) have the same number of digits.at n=24A082994
• a(n) is the difference between the largest and smallest integer solutions to n=x/pi(x), where pi(x) = A000720(x).at n=37A087236
• Triangle V(l,p) (l>=0, p=0..l) read by rows: see Formula for definition, see Comments for motivation.at n=96A179898
• Triangle read by rows: the X-transformation of the Catalan triangle A033184.at n=31A228334
• Fixed points of A153212: After a(1) = 1, numbers of the form p_i1^i1 * p_i2^(i2-i1) * p_i3^(i3-i2) * ... * p_ik^(ik-i_{k-1}), where p_i's are distinct primes present in the prime factorization of n, with i1 < i2 < i3 < ... < ik, and k = A001221(n) and ik = A061395(n).at n=36A242421
• Numbers n such that there exists an m so that squarefree kernel of n = squarefree kernel of m, and n is the sum of the proper divisors of m (m may equal n).at n=21A252234
• Numbers A055744(n) such that for any k < n, A055744(k) and A055744(n) do not have all their prime factors in common.at n=20A256431
• The sum of the numbers on the perimeter of the n X n diamond frame, located at the top of the numerical pyramid containing the positive integers in natural order.at n=26A359096