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Search: id:A129450
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| A129450 |
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a(n) = smallest perfect power that begins and ends with digit n, 1 <= n<= 9; one-digit numbers are excluded. |
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+0
2
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| 121, 21952, 343, 484, 5625, 676, 79507, 8242408, 9409
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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a(8) = 202^3 = 8242408; there is no smaller perfect power that begins and ends with digit 8.
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PROGRAM
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(MAGMA) PP:=[1] cat [ n: n in [2..9000000] | IsPower(n) ]; firstlast:=function(x); for n:=1 to #PP do k:=Intseq(PP[n], 10); if #k gt 1 and k[1] eq x and k[ #k] eq x then return PP[n]; end if; end for; return -1; end function; [ firstlast(d): d in [1..9] ]; /* Klaus Brockhaus, Apr 16 2007 */
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CROSSREFS
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Cf. A001597 (perfect powers), A075786 (palindromic perfect powers), A128827.
Adjacent sequences: A129447 A129448 A129449 this_sequence A129451 A129452 A129453
Sequence in context: A078277 A050740 A121013 this_sequence A082489 A028463 A013749
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KEYWORD
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nonn,base,fini,full
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AUTHOR
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J. M. Bergot (thekingfishb(AT)yahoo.ca), Apr 12 2007
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EXTENSIONS
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Edited, corrected and extended by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Apr 16 2007
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