18859

Properties

Appears in sequences

• Primes setting records for earliest alphabetical position in American English.at n=16A050444
• Hard numbers: a(n) = smallest positive number m with f(m) = n, where f(m) is the smallest number of digits that are needed to construct m using only 1's, 2's and any number of +, -, *, ^ signs, not allowing concatenation of the digits.at n=13A060274
• Minimal Thompson primes: a(n) is the smallest prime expressible as p1*p2*...*pk-q1*q2*...*qj, where k+j=n and {p1,...,qj} are the first n primes.at n=9A060772
• Write product of first n primes as x*y with x<y and x maximal; sequence gives value of y-x.at n=11A061060
• Smallest prime which occurs exactly n times in the sequence A086527.at n=18A086528
• Primes with digit sum = 31.at n=26A106767
• Number of base 19 circular n-digit numbers with adjacent digits differing by 1 or less.at n=8A124712
• Primes congruent to 38 mod 59.at n=35A142765
• Primes congruent to 10 mod 61.at n=39A142808
• Primes congruent to 32 mod 67.at n=36A154621
• Primes p such that p1 = ceiling(p/2) + p is prime and p2 = floor(p1/2) + p1 is prime.at n=40A158714
• Number of lines through at least 2 points of a 9 X n grid of points.at n=32A160849
• Emirps whose only prime digits are 5's.at n=28A179036
• Emirps with a 5 as the only prime digit.at n=22A179037
• a(n) = min(p +- q) > 1 with p*q being equal to the n-th primorial (A002110).at n=10A246463
• Number of (n+1)X(2+1) 0..2 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)-x(i-1,j) in the j direction.at n=3A250521
• Number of (n+1)X(4+1) 0..2 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)-x(i-1,j) in the j direction.at n=1A250523
• T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)-x(i-1,j) in the j direction.at n=11A250527
• T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)-x(i-1,j) in the j direction.at n=13A250527
• Smallest number requiring n digits for its representation in the "Terrible Twos Problem" without using multidigit expressions.at n=12A260016