A052474 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 main diagonal.

1, 2, 4, 7, 12, 13, 14, 15, 16, 18, 20, 21, 22, 23, 32, 35, 36, 39, 42, 48, 49, 50, 51, 53, 54, 57, 58, 59, 61, 62, 64, 66, 68, 76, 77, 78, 80, 82, 86, 87, 89, 91, 92, 93, 98, 103, 109, 110, 118, 124, 127, 128, 129, 132, 133, 135, 136, 139, 140, 141, 142, 143, 149

Offset

1,2

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..150

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)
a052474 n = a056230_tabl !! (n-1) !! 0
-- Reinhard Zumkeller, Nov 19 2011

Crossrefs

Cf. A057153 (first row), A057154 (numbers not used), A056230 (array), A056231, A056232, A056233, A056234.

Sequence in context: A384378 A193841 A394573 * A033054 A396011 A361724

Adjacent sequences: A052471 A052472 A052473 * A052475 A052476 A052477

Keyword

nice,nonn,easy

Author

Jonas Wallgren, Jul 30 2000

Status

approved