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A057154
Construct difference array so that (1) first row begins with 1, (2) every row is monotonic increasing, (3) no number appears more than once, (4) smallest number not yet used begins a new row. Sequence gives numbers not used.
8
5, 8, 10, 24, 28, 33, 37, 40, 46, 63, 69, 70, 83, 85, 94, 95, 102, 105, 106, 112, 113, 114, 119, 131, 145, 147, 148, 152, 161, 165, 166, 175, 181, 197, 203, 207, 215, 221, 235, 236, 239, 247, 253, 254, 267, 270, 276, 286, 289, 290, 296, 307, 309, 315, 317, 322
OFFSET
1,1
LINKS
EXAMPLE
Array begins
1 3 9 26 73 194 ...
.2 6 17 47 121 ...
. 4 11 30 74 ...
.. 7 19 44 ...
... 12 25 ...
.... 13 ...
PROG
(Haskell)
import Data.List (intersect, union, (\\))
a057154 n = a057154_list !! (n-1)
a057154_list = g [1] [2..] [1] where
g ds (a:as) us
| null (ds' `intersect` us) = g ds' (as \\ ds') (us `union` ds')
| otherwise = a : g ds as us
where ds' = scanl (+) a ds
-- Reinhard Zumkeller, Nov 19 2011
CROSSREFS
Cf. A057153 (first row), A052474 (main diagonal), A056230 (array), A056231, A056232, A056233, A056234.
Sequence in context: A157482 A314385 A185001 * A072524 A240968 A187878
KEYWORD
nice,nonn,easy
AUTHOR
Jonas Wallgren, Jul 30 2000
EXTENSIONS
More terms from Rob Speer (rob(AT)twcny.rr.com) and Loren Merritt, Aug 14 2000
Further terms from Larry Reeves (larryr(AT)acm.org), May 09 2001
STATUS
approved