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Search: id:A005348
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| A005348 |
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Number of ways to add n ordinals.
(Formerly M1435)
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+0
1
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| 1, 2, 5, 13, 33, 81, 193, 449, 1089, 2673, 6561, 15633, 37249, 88209, 216513, 531441, 1266273, 3017169, 7189057, 17537553, 43046721, 102568113, 244390689, 582313617
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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Wakulicz, A. Sur la somme d'un nombre fini de nombres ordinaux. Fund. Math. 36 (1949), 254-266; 38 (1951), 239.
P. Erdos, Some remarks on set theory, Proc. Am. Math. Soc. 1 (1950) 127-141.
W. Sierpinski, Cardinal and Ordinal Numbers, 2nd ed. p 275.
R. K. Guy, The second strong law of small numbers. Math. Mag. 63 (1990), no. 1, 3-20.
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LINKS
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Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
A. Wakulicz, Sur la somme d'un nombre fini de nombres ordinaux, Fund. Math. 36 (1949), 254-266.
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FORMULA
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a(n)=81*a(n-5) for n >= 21.
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CROSSREFS
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Adjacent sequences: A005345 A005346 A005347 this_sequence A005349 A005350 A005351
Sequence in context: A001659 A088921 A005183 this_sequence A067676 A116703 A116724
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KEYWORD
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nonn,easy
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AUTHOR
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njas, R. K. Guy, Bill Sands and Tommy Kucera.
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