40240

Appears in sequences

• a(n) is the concatenation of n and 6n.at n=39A009440
• Numbers k such that the number of primes between k and 2k (inclusive) is equal to the number of primes between k and reverse(k) (inclusive).at n=35A074814
• First differences of A057809.at n=37A087238
• Expansion of x*(x^3+3*x^2-1)*(5*x^4-5*x^2+1) / ( -1+x+8*x^2-7*x^3-21*x^4+15*x^5+20*x^6-10*x^7-5*x^8+x^9 ).at n=21A122604