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Search: id:A062739
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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
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OFFSET
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1,2
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REFERENCES
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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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FORMULA
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It is not true that a(n)=A001694(2n-1).
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EXAMPLE
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Consecutive-odd examples from Sentance: {25,27},{70225,70227},{189750625,189750627}
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MATHEMATICA
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Powerful[n_Integer] := (n ==1) || Min[Transpose[FactorInteger[n]][[2]]]>=2; Select[Range[5000], OddQ[ # ]&&Powerful[ # ]&] - T. D. Noe (noe(AT)sspectra.com), May 04 2006
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CROSSREFS
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Cf. A001694, A060355, A060859, A060860.
Cf. A076445 (consecutive odd powerful numbers).
Sequence in context: A089091 A053850 A020210 this_sequence A075109 A117580 A020308
Adjacent sequences: A062736 A062737 A062738 this_sequence A062740 A062741 A062742
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Jul 12 2001
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EXTENSIONS
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Checked by T. D. Noe (noe(AT)sspectra.com), May 04 2006
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