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A062739
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Odd powerful numbers.
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2
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1, 9, 25, 27, 49, 81, 121, 125, 169, 225, 243, 289, 343, 361, 441, 529, 625, 675, 729, 841, 961, 1089, 1125, 1225, 1323, 1331, 1369, 1521, 1681, 1849, 2025, 2187, 2197, 2209, 2401, 2601, 2809, 3025, 3087, 3125, 3249, 3267, 3375, 3481, 3721, 3969, 4225
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Smallest term of this sequence not also in A075109 is 675, followed by 1125. - Alonso del Arte, Nov 22 2011
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REFERENCES
| R. K. Guy, Unsolved Problems in Number Theory, B16
W. A. Sentance, Occurrences of consecutive odd powerful numbers. Amer. Math. Monthly, 88:272-274.
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LINKS
| Moshe Levin, Table of n, a(n) for n = 1..10000
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FORMULA
| It is not true that a(n)=A001694(2n-1).
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EXAMPLE
| Consecutive-odd examples from Sentance: {25,27},{70225,70227},{189750625,189750627}
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MATHEMATICA
| Powerful[n_Integer] := (n ==1) || Min[Transpose[FactorInteger[n]][[2]]]>=2; Select[Range[5000], OddQ[ # ]&&Powerful[ # ]&] (* T. D. Noe, May 04 2006 *)
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CROSSREFS
| Cf. A001694, A060355, A060859, A060860.
Cf. A076445 (consecutive odd powerful numbers).
Sequence in context: A155109 A053850 A020210 * A075109 A117580 A020308
Adjacent sequences: A062736 A062737 A062738 * A062740 A062741 A062742
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Jul 12 2001
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EXTENSIONS
| Checked by T. D. Noe, May 04 2006
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