2100225

Appears in sequences

• The (2^n+1)-th triangular number (cf. A000217).at n=11A028401
• Number of lines in a Pauli graph of order n.at n=9A127069
• 1/4 the number of (n+1) X 2 binary arrays with all 2 X 2 subblock sums the same.at n=21A183978
• Fold a square sheet of paper alternately vertically to the left and horizontally downwards; after each fold, draw a line along each inward crease; after n folds, the resulting graph has a(n) regions with minimal area.at n=25A342763
• Triangular numbers that are binary palindromes.at n=29A350987