19663

Appears in sequences

• Numbers whose base-4 representation contains exactly three 0's and four 3's.at n=26A045080
• Numbers k such that the squarefree part of k equals A062799(k).at n=30A069551
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, -1, 1), (-1, 1, 1), (1, 0, -1), (1, 0, 1)}.at n=9A148767
• Least positive integer b such that (n, b, n+b) is an abc-hit.at n=19A272236
• Least positive integer b such that b > n and (n, b, n+b) is an abc-hit.at n=19A272239
• Expansion of exp( Sum_{n>=1} sigma(8*n)*x^n/n ) in powers of x.at n=5A283120
• Index of first occurrence of n appearing twice in succession in van Eck's sequence (A181391), or 0 if it never occurs.at n=33A308782
• Numbers p^2*q, p > q odd primes such that q does not divide p-1, and q does not divide p+1.at n=36A350421
• Least k such that there are exactly n ways to choose a sequence of divisors, one of each element of the multiset of prime indices of k (with multiplicity).at n=43A355732
• Numbers k such that sigma(k) = psi(k) + tau(k) + omega(k).at n=14A386637
• Numbers k such that sigma(k) = psi(k) + omega(k)^3.at n=49A390252