69751

Appears in sequences

• Strong pseudoprimes to base 84.at n=20A020310
• Strong pseudoprimes to base 86.at n=19A020312
• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 33 ones.at n=21A031801
• Odd triangular numbers with prime indices.at n=35A034954
• Number of powers x^y (x,y > 1) with n digits.at n=9A060298
• Triangular numbers with sum of digits = 28.at n=18A068132
• Triangular numbers which are one more than a product of distinct triangular numbers.at n=28A083517
• Triangular numbers equal to the sum of a prime number with its index.at n=28A115886
• Hexagonal numbers for which the sum of the digits is also a hexagonal number.at n=37A117062
• Triangular numbers T such that T+10 is the next prime after T.at n=12A129540
• 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, 1), (-1, 1, -1), (0, 0, 1), (1, 0, 0)}.at n=11A149812
• a(n) = n*(n+1)*(11*n +10)/6.at n=33A254407
• The phi-radical numbers: composite numbers m such that rad(phi(m)) = rad(m-1).at n=9A306478
• Hexagonal numbers that are sphenic numbers.at n=36A380007