18619

Appears in sequences

• Composite numbers whose prime factors contain no digits other than 3 and 4.at n=23A036314
• Least k such that k*10^n+1, k*10^n+3, k*10^n+7 and k*10^n+9 are all prime.at n=16A064281
• Numerators of convergents to Thue-Morse constant.at n=11A085394
• Indices m such that A128646(m)-1 is prime, where A128646 = denominator of partial sums of 1/(p(i)-1).at n=43A137689
• Numbers n with nonzero digits such that n*(product of digits of n) is a palindrome.at n=36A229550
• Numbers n such that phi(n) = 3*phi(n+1).at n=7A256907
• Expansion of Product_{j>=1} 1/(1 - (-1 + Product_{k>=1} 1/(1 - x^k))^j).at n=9A307127
• Numbers k such that 407*2^k+1 is prime.at n=21A323103
• a(n) = number of nonnegative integers that are not the sum of {2 squares, a nonnegative 5th power, and a nonnegative n-th power}.at n=23A332664