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A018790
Number of subsets of { 1, ..., n } containing an A.P. of length 5.
0
0, 0, 0, 0, 0, 1, 3, 8, 20, 56, 144, 332, 751, 1803, 4163, 9401, 20404, 45169, 98753, 213575, 457945, 990624, 2119184, 4493766, 9460916, 19947914, 41567180, 86219409, 178237782, 369985101, 765030649, 1572706886, 3224800994, 6617409989
OFFSET
0,7
CROSSREFS
Sequence in context: A018035 A271843 A122228 * A268042 A009436 A354519
KEYWORD
nonn
STATUS
approved