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Search: id:A075309
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| A075309 |
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Distinct-digit perfect powers. |
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+0 6
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| 1, 4, 8, 9, 16, 25, 27, 32, 36, 49, 64, 81, 125, 128, 169, 196, 216, 243, 256, 289, 324, 361, 512, 529, 576, 625, 729, 784, 841, 961, 1024, 1089, 1296, 1369, 1728, 1764, 1849, 1936, 2048, 2187, 2197, 2304, 2401, 2601, 2704, 2809, 2916, 3025, 3125, 3249, 3481
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Of 1110 perfect powers < 1000000, 259 are distinct-digit.
Sequence is finite. What is the index of the last term? Note that 2^30 = 1073741824, hence the highest power that occurs < 30. The frequency chart of a power r, 2 < r < 30 may be of some interest and could be included. - Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Dec 06 2003
There are a total of 657 distinct terms, the last of which is 99066^2=9814072356. The highest power occurs in 2^29. There are 609 squares, 39 cubes, 19 fourth powers, 9 fifth powers, 4 sixth powers, 4 seventh powers, 3 eighth powers, 2 ninth powers, 2 tenth powers and one each of powers 11, 12, 13, 14, 15, 20 and 29. These counts to not add to 657 because 1 is not counted and some powers, such as 2^4=4^2=16, are counted twice. - T. D. Noe (noe(AT)sspectra.com), Aug 09 2005
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..657
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EXAMPLE
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100,121,144,343 etc. are not members.
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MATHEMATICA
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lst={1}; Do[k=1; While[k++; n=k^pow; n<10^10, d=IntegerDigits[n]; If[Length[Union[d]]==Length[d], AppendTo[lst, n]]], {pow, 2, 29}]; lst=Union[lst] (Noe)
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CROSSREFS
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Cf. A090516, A001597.
Adjacent sequences: A075306 A075307 A075308 this_sequence A075310 A075311 A075312
Sequence in context: A076292 A090516 A090515 this_sequence A052054 A046447 A087244
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KEYWORD
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easy,nonn,base,fini
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AUTHOR
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Zak Seidov (zakseidov(AT)yahoo.com), Oct 11 2002
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EXTENSIONS
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More terms from David Wasserman (dwasserm(AT)earthlink.net), Jan 16 2005
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