268468225

Appears in sequences

• a(n) = (2^n + 1)^2.at n=14A028400
• Squares which are palindromes in base 4.at n=21A029987
• a(2*n) = -(2^(2*n+1) + 1), a(2*n+1) = (2^(n+1) - (-1)^n)^2.at n=27A105951
• a(2n) = 2*4^n-1, a(2n+1) = (2^(n+1)+1)^2; interlaces A083420 with A028400.at n=27A107663
• Maximum number of rational points on a smooth absolutely irreducible projective curve of genus 1 over the field F_2^n.at n=27A169872
• a(n) = 1+4^(n+1)-4*(-2)^n.at n=13A171590
• Square array A(n,k), n>=0, k>=0, read by antidiagonals: A(n,k) is the number of partitions of 2^2^n into powers of 2 less than or equal to 2^k.at n=25A172288
• 1/4 the number of (n+1) X 2 binary arrays with all 2 X 2 subblock sums the same.at n=28A183978
• Numbers k such that k^4 is sum of two positive 7th powers.at n=18A291830
• a(n) = Sum_{d|n} tau(d)^n, where tau(n) is the number of divisors of n.at n=13A344080
• a(n) is the least perfect power > 2^n.at n=28A357751