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A081880 Triangle read by rows: n-th row gives trajectory of 2n under the map x->(x^2-4)/6, stopping when the next term would be negative or nonintegral. 0
0, 2, 0, 4, 2, 0, 6, 8, 10, 16, 42, 10, 16, 42, 12, 14, 32, 170, 4816, 3865642, 2490531345360, 16, 42, 18, 20, 66, 22, 80, 1066, 189392, 5978221610, 5956522269711832016, 5913359591595499145281505571167104042, 5827970276585748074286667660065476529979312208145367609757859954142122960, 24, 26 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..35.

Pierre Abbat, The 64-100 Sequences

EXAMPLE

8 -> (64-4)/6 = 10 -> (100-4)/6 = 16 -> (256-4)/6 = 42 -> (42^2-4)/6 nonintegral, so stop; thus row 4 is (8, 10, 16, 42).

Triangle begins:

0,

2, 0,

4, 2, 0,

6,

8,

10, 16, 42, 10, 16, 42,

12,

14, 32, 170, 4816, 3865642, 2490531345360,

16, 42,

18,

20, 66,

22, 80, 1066, 189392, 5978221610, 5956522269711832016, 5913359591595499145281505571167104042, 5827970276585748074286667660065476529979312208145367609757859954142122960,

24,

...

CROSSREFS

Sequence in context: A319690 A341419 A185879 * A144289 A293815 A339941

Adjacent sequences:  A081877 A081878 A081879 * A081881 A081882 A081883

KEYWORD

nonn,tabf

AUTHOR

Pierre Abbat, Apr 12, 2003

STATUS

approved

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Last modified May 23 09:46 EDT 2022. Contains 353975 sequences. (Running on oeis4.)