122011

Properties

Appears in sequences

• Number of 3 X 3 X 3 magic cubes with sum 3n.at n=14A070302
• Expansion of the exponential series exp( x R(x) ) = exp((1 + x - sqrt(1 - 2 x - 3x^2))/(2(1 + x))), where R(x) is the ordinary generating series of the Riordan numbers A005043.at n=7A080895
• Factorial expansions of the entries in A085216.at n=17A085218
• Primes whose decimal representation also represents a prime in base 3.at n=22A089981
• Primes p such that the p-1 digits of the binary expansion of k/p (for k=1,2,3,...,p-1) fit into the k-th row of a magic square grid of order p-1.at n=26A096339
• Prime numbers that contain the string "2011" in their decimal expansion.at n=5A191421
• Palindromic primes in the sense of A007500 with digits '0', '1' and '2' only.at n=10A199302
• Emirps that become their own reversals when rotated through 180 degrees (including on calculator display).at n=33A209620
• Numbers k that are the representation of primes in base 3 and in base 4.at n=22A340290
• a(n) = n! * Sum_{k=0..floor(n/3)} (-n)^k * binomial(n-2*k,k)/(n-2*k)!.at n=7A362305
• Prime numbersat n=11476