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Search: id:A066757
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| A066757 |
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Pentagonal numbers whose reverse is triangular. |
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+0
1
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| 0, 1, 12, 51, 18426, 69876, 6168162, 12105501, 17759001, 3008521945, 100938635992, 826471253301
(list; graph; listen)
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OFFSET
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0,3
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EXAMPLE
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51 is pentagonal and 15 is triangular
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MATHEMATICA
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dtn[L_] := Fold[10#1+#2&, 0, L] tritest[n_] := Module[{t}, t=Floor[N[Sqrt[2n]]]; 2n==t(t+1)] A={0}; For[i=1, i>0, i++, t=i(3i-1)/2; r=dtn[Reverse[IntegerDigits[t]]]; If[tritest[r]&&Mod[t, 10]>0, AppendTo[A, t]; Print[A]]]
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CROSSREFS
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Sequence in context: A145886 A166776 A115680 this_sequence A045219 A054410 A030182
Adjacent sequences: A066754 A066755 A066756 this_sequence A066758 A066759 A066760
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KEYWORD
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base,more,nonn
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AUTHOR
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Erich Friedman (efriedma(AT)stetson.edu), Jan 17 2002
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