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A175039
Minimum number of integer-sided squares needed to tile an n-row staircase (a figure with n unit squares in the n-th row, and the leftmost squares of each row vertically aligned).
1
1, 3, 3, 7, 6, 7, 7, 11, 12, 13, 12, 15, 14, 15, 15, 20, 20, 23, 22, 23, 24, 25, 24, 29, 28, 29, 28
OFFSET
1,2
COMMENTS
a(n) >= n, since the rightmost squares in each row must be covered by distinct tiles.
a(n) = n iff n = 2^k - 1.
a(n) = n+1 iff n = 2^k - 2^m - 1.
a(2*k) <= 2*a(k) + 1, a(2*k+1) <= 2*a(k) + 1 for k >= 1. - Jinyuan Wang, Jul 17 2019
a(n) <= A003817(n). - Austin Shapiro, Dec 29 2022
LINKS
EXAMPLE
See link for diagrams of tilings.
CROSSREFS
Solutions for a(n) = n: A000225. Solutions for a(n) = n+1: A030130, excluding 0.
Sequence in context: A200690 A045773 A256700 * A222405 A146970 A078708
KEYWORD
nonn,more
AUTHOR
Cyril Zhang, Apr 04 2010
STATUS
approved