122424

Appears in sequences

• Least n-digit multiple of n such that the r-th digit is prime if r is a prime else it is composite. The location and value of the most significant digit is 1. 0 if no such number exists.at n=5A113572
• a(n) is the least n-digit number whose k-th digit is prime if k is prime, composite if k is composite, and 1 if k=1.at n=5A113574
• Array read by antidiagonals: T(m,n) = Sum(1<=i<=m) i * ( n + 2(i-1) )!at n=17A211366
• Concatenation of the first n entries of the difference sequence of prime numbers (see A001223).at n=5A255307
• Consider constructing binary words that begin with 0 such that the subword 00, whenever it appears, is followed by 111. Then a(n) counts such words at length n (including those where the string 111 is yet being completed - see Example).at n=22A340215