31145

Appears in sequences

• Numbers n such that n divides the (left) concatenation of all numbers <= n written in base 21 (most significant digit on right and removing all least significant zeros before concatenation).at n=12A029538
• Numbers k such that 6*k+1, 6*k+7, 6*k+13, 6*k+19 are consecutive primes.at n=28A090839
• Second elementary symmetric function of the first n terms of (1,2,2,3,3,4,4,5,5...).at n=28A203298
• Number of numbers x < 10^n such that the digits of x^2 occur with an equal frequency of 2.at n=7A225428
• First row of spectral array W(log(Pi)).at n=10A249329
• Duplicate of A090839.at n=28A296055