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A033618
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Number of ways n-th repdigit number (A010785[ n ]) can be expressed as a polygonal number.
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0
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2, 2, 2, 2, 3, 2, 2, 3, 2, 3, 3, 2, 4, 5, 2, 3, 3, 4, 3, 4, 3, 4, 5, 3, 3, 3, 3, 2, 3, 3, 3, 6, 3, 2, 3, 2, 3, 3, 3, 3, 4, 2, 3, 3, 7, 3, 4, 3, 4, 5, 4, 3, 4, 2, 2, 3, 3, 3, 4, 3, 3, 3, 3, 4, 3, 2, 3, 6, 2, 3, 3
(list; graph; refs; listen; history; internal format)
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OFFSET
| 2,1
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LINKS
| M. Keith, On Repdigit Polygonal Numbers, J. Integer Sequences, Vol. 1, 1998, #6.
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EXAMPLE
| The n-th k-sided polygonal number is P(n,k)=n((k-2)n+4-k)/2 (k >= 2, n >= 1). For each repdigit number R>=2, sequence gives number of (n,k) such that P(n,k)=R.
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CROSSREFS
| Sequence in context: A074592 A089993 A047931 * A061357 A138139 A127992
Adjacent sequences: A033615 A033616 A033617 * A033619 A033620 A033621
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KEYWORD
| nonn,base
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AUTHOR
| Mike Keith (domnei(AT)aol.com)
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