224123

Appears in sequences

• Concatenation of n in base 2 up to base 10 and n in base 10 down to base 2 is prime, all numbers are interpreted as decimals.at n=30A054258
• a(1) = 1 thereafter a(n) = Sum_{k=1..n-1} ceiling(a(n-k)/k).at n=26A100482