131105

Appears in sequences

• a(n) = 2^n + 2*n - 1.at n=17A061761
• Start with Pascal's triangle; form a triangle by sliding down n steps from top on both sides and including the horizontal row, deleting the inner numbers; a(n) = sum of entries on perimeter of triangle.at n=17A081494
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 1, 0), (-1, 1, 1), (1, 0, -1), (1, 1, 0)}.at n=10A149158
• Positive integers with the same number of 1s in base 10 and base 2.at n=18A153115
• Sums of three Mersenne primes.at n=38A174055
• 4-step Fibonacci sequence starting with 0, 1, 1, 0.at n=21A251654
• Bitmaps of king + rook vs. king checkmate patterns on a standard 8 X 8 board.at n=13A362950