78409

Appears in sequences

• Strong pseudoprimes to base 76.at n=33A020302
• Strong pseudoprimes to base 90.at n=23A020316
• Numbers k such that the sum of the first k odd composites is palindromic.at n=9A058848
• Composite and every divisor (except 1) contains the digit 8.at n=19A062678
• Composite numbers k such that k divides F(k-1) where F(j) are the Fibonacci numbers.at n=22A069106
• Least nonsquare whose remainder modulo k^2 is a square for all 0 < k <= n.at n=10A081650
• Numbers k that divide Fibonacci(k-1) but do not divide Fibonacci(k) - 1.at n=11A094410
• a(n) = 72*n^2 + 1.at n=33A158740
• Semiprimes k that divide Fibonacci(k-1).at n=12A177086
• p^2 + (p+2)^2 - 1 where (p,p+2) is the n-th twin prime pair.at n=14A184417
• Nonprime n not divisible by 2 or 3 such that Fibonacci(n-1) is congruent to (1 - Legendre(n,5))/2 modulo n.at n=28A220292
• Egyptian fraction representation of sqrt(34) (A010489) using a greedy function.at n=5A248261
• Start with a square; at each stage add a square at each expandable vertex so that the ratio of the side of the squares at stage n+1 and at stage n is the golden ratio phi=0.618...; a(n) is the number of squares at n-th stage.at n=12A269962
• a(n) is the smallest composite squarefree number k such that (p+n) | (k-1) for every prime p dividing k.at n=9A274445
• Semiprimes k such that k+4, k+6, k+9, k+10 and k+14 are also semiprimes.at n=21A360666