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A080810
a(1) = 7, a(n)= smallest n-th power obtained by inserting digits anywhere in a(n-1).
5
7, 576, 17576, 1475789056, 1420778345789277056227207, 149247077443060991182553045537892735703095362592472033442634721
OFFSET
1,1
EXAMPLE
24^2=576. 26^3=17576. 196^4=1475789056. 67687^5=1420778345789277056227207.
MAPLE
buffedStr := proc(n, candid) local f ; if length(n) = 0 then RETURN(true) ; fi ; f := SearchText(substring(n, 1), candid) ; if f = 0 then RETURN(false) ; else if buffedStr(substring(n, 2..-1), substring(candid, f+1..-1)) = true then RETURN(true) ; else RETURN(false) ; fi ; fi ; end: A080810 := proc(preva, n) local i, tst ; i := 1 ; while true do tst := i^n ; if buffedStr(convert(preva, string), convert(tst, string)) = true then RETURN(tst) ; fi ; i := i+1 ; od: end: an :=7 ; for n from 2 to 15 do an := A080810(an, n) ; end ; # R. J. Mathar, Sep 20 2006
KEYWORD
base,more,nonn
AUTHOR
Amarnath Murthy, Mar 22 2003
EXTENSIONS
Corrected and extended by R. J. Mathar, Sep 20 2006
One more term. Sean A. Irvine, Sep 01 2009
STATUS
approved