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A050548
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Iterated triangular numbers.
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1
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7, 28, 406, 82621, 3413156131, 5824817388998022646, 16964248807586870937449001943463431981, 143892868802856286225154411591351342616163027795335641150249224655238508171
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| a(8) has 149 digits. [From Harvey P. Dale, May 08 2011]
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FORMULA
| a(n)=binomial(a(n-1)+1, 2), a(0)=7
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MATHEMATICA
| NestList[Binomial[#+1, 2]&, 7, 10] (* From Harvey P. Dale, May 08 2011 *)
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CROSSREFS
| A000217, A007501, A013589.
Sequence in context: A198028 A203209 A193288 * A140447 A038934 A041088
Adjacent sequences: A050545 A050546 A050547 * A050549 A050550 A050551
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KEYWORD
| easy,nice,nonn
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AUTHOR
| Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Dec 29 1999
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EXTENSIONS
| a(7) provided by Harvey P. Dale, May 08 2011.
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