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A117678
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Squares for which the multiplicative digital root is also a square.
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1
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0, 1, 4, 9, 25, 100, 169, 196, 225, 256, 400, 529, 576, 625, 676, 900, 961, 1024, 1089, 1156, 1225, 1296, 1521, 1600, 2025, 2209, 2304, 2401, 2500, 2601, 2704, 2809, 2916, 3025, 3136, 3481, 3600, 3844, 3969, 4096, 4225, 4356, 4489, 4900, 5041, 5184, 5329
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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LINKS
| Nathaniel Johnston, Table of n, a(n) for n = 1..5000
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MAPLE
| A007954 := proc(n) return mul(d, d=convert(n, base, 10)): end: A117678 := proc(n) option remember: local k, m: if(n=1)then return 0:fi: for k from procname(n-1)+1 do m:=k^2: while(length(m)>1)do m:=A007954(m): od: if(m in {0, 1, 4, 9})then return k: fi: od: end: seq(A117678(n)^2, n=1..47); # Nathaniel Johnston, May 05 2011
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CROSSREFS
| Cf. A000290, A116978.
Sequence in context: A184326 A176497 A028400 * A167045 A055851 A025494
Adjacent sequences: A117675 A117676 A117677 * A117679 A117680 A117681
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KEYWORD
| nonn,easy,base
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AUTHOR
| Luc Stevens (lms022(AT)yahoo.com), Apr 12 2006
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EXTENSIONS
| Offset and some terms corrected by Nathaniel Johnston (nathaniel(AT)nathanieljohnston.com), May 05 2011
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