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A053715
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Triangular numbers (the sum of the first n integers) in base n.
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1
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0, 1, 11, 20, 22, 30, 33, 40, 44, 50, 55, 60, 66, 70, 77, 80, 88, 90, 99, 100, 110, 110, 121, 120, 132, 130, 143, 140, 154, 150, 165, 160, 176, 170, 187, 180, 198, 190, 209, 200, 220, 210, 231, 220, 242, 230, 253, 240, 264, 250, 275, 260, 286, 270, 297, 280
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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LINKS
| Harry J. Smith, Table of n, a(n) for n=0,...,1000
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FORMULA
| Apart from a(1), a(2n-1)=10n and a(2n)=11n
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EXAMPLE
| a(3) = 1+2+3=6 = 20 base 3
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PROG
| (PARI) baseE(x, b)= { local(d, e=0, f=1); if (b<2, return(x)); while (x>0, d=x%b; x\=b; e+=d*f; f*=10); return(e) } { for (n=0, 1000, write("b053715.txt", n, " ", baseE(n*(n + 1)/2, n)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Apr 27 2010]
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CROSSREFS
| Cf. A000217.
Sequence in context: A105958 A124250 A124251 * A038581 A044054 A044435
Adjacent sequences: A053712 A053713 A053714 * A053716 A053717 A053718
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KEYWORD
| base,easy,nonn
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AUTHOR
| Henry Bottomley (se16(AT)btinternet.com), Feb 10 2000
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EXTENSIONS
| More terms from James A. Sellers (sellersj(AT)math.psu.edu), Feb 22 2000
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