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 A167038 Squares that remain squares when prefixed with a 4. 1
 9, 225, 900, 2025, 22500, 90000, 202500, 950625, 2250000, 9000000, 20250000, 85100625, 95062500, 225000000, 900000000, 2025000000, 2487515625, 8510062500, 9506250000, 18123890625, 22500000000, 90000000000, 202500000000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE 9 = 3^2 is a square and becomes the square 49 = 7^2 if a 4 is attached in front of its decimal representation. MAPLE P:=proc(i) local a, n; for n from 1 by 1 to i do a:=4*10^floor(1+log10(n^2))+n^2; if a=trunc(sqrt(a))^2 then print(n^2); fi; od; end: P(1000000000000); [From Paolo P. Lava, Nov 02 2009] CROSSREFS Sequence in context: A014736 A017558 A159939 * A074190 A069075 A218659 Adjacent sequences:  A167035 A167036 A167037 * A167039 A167040 A167041 KEYWORD nonn,base AUTHOR Claudio Meller, Oct 27 2009 EXTENSIONS Keyword:base added by R. J. Mathar, Oct 28 2009 STATUS approved

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