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A013580
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Triangle formed in same way as Pascal's triangle (A007318) except 1 is added to central element in even-numbered rows.
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2
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1, 1, 1, 1, 3, 1, 1, 4, 4, 1, 1, 5, 9, 5, 1, 1, 6, 14, 14, 6, 1, 1, 7, 20, 29, 20, 7, 1, 1, 8, 27, 49, 49, 27, 8, 1, 1, 9, 35, 76, 99, 76, 35, 9, 1, 1, 10, 44, 111, 175, 175, 111, 44, 10, 1, 1, 11, 54, 155, 286, 351, 286, 155, 54, 11, 1, 1, 12, 65, 209, 441, 637, 637, 441, 209, 65
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 0,5
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FORMULA
| G.f.: 1/(1-(1+y)*x)/(1-y*x^2). - Vladeta Jovovic (vladeta(AT)eunet.rs), Oct 12 2003
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EXAMPLE
| 1; 1,1; 1,3,1; 1,4,4,1; 1,5,9,5,1; ...
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CROSSREFS
| Row sums give A000975, A054106.
Sequence in context: A028262 A173117 A050177 * A147290 A026670 A131402
Adjacent sequences: A013577 A013578 A013579 * A013581 A013582 A013583
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KEYWORD
| tabl,nonn,easy
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AUTHOR
| Martin Hecko (bigusm(AT)interramp.com)
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EXTENSIONS
| More terms from James A. Sellers (sellersj(AT)math.psu.edu)
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