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 A171976 Numbers n such that the sum of the squares of the digits of n^n is a square. 0
 0, 1, 2, 8, 10, 100, 123, 209, 312, 1000, 1668, 2191, 2268, 4767, 9338, 10000, 11004, 12248, 12322, 15926, 17951, 18202, 19764, 21807, 29509, 42647, 43072, 44750, 54237, 56634, 70383, 74032, 85325, 90906, 95261, 100000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS FORMULA {n: A003132(n^n) in A000290}. {n: n^n in A175396.} EXAMPLE 8 is in the sequence because 8^8 = 16777216 and 1^2+6^2+7^2+7^2+7^2+2^2+1^2+6^2   = 225 = 15^2. MAPLE with(numtheory): digits:=200:nn:=5000:for n from 0 to nn do:l:=length(n^n):n0:=n^n:s:=0:for   m from 1 to l do:q:=n0:u:=irem(q, 10):v:=iquo(q, 10):n0:=v :s:=s+u^2:od:if sqrt(s)=   floor(sqrt(s))then printf(`%d, `, n):else fi:od: MATHEMATICA Join[{0}, Select[Range[100000], IntegerQ[Sqrt[Total[IntegerDigits[ #^#]^2]]]&]] (* Harvey P. Dale, Sep 25 2018 *) PROG (PARI) isok(n) = my(d = digits(n^n)); issquare (sum(i=1, #d, d[i]^2)); \\ Michel Marcus, Jan 15 2014 CROSSREFS Sequence in context: A230826 A071184 A174153 * A081231 A229128 A121715 Adjacent sequences:  A171973 A171974 A171975 * A171977 A171978 A171979 KEYWORD nonn,base AUTHOR Michel Lagneau, Nov 19 2010 EXTENSIONS Edited by D. S. McNeil, Nov 19 2010 Offset corrected and more terms added, Michel Marcus, Jan 15 2014 STATUS approved

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Last modified April 11 14:58 EDT 2021. Contains 342886 sequences. (Running on oeis4.)