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Squares of the form u'v'w, where in decimal representation u=n^2, v=2*n^2 and w=n^2 possibly with a leading zero.
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%I #10 Dec 26 2023 18:06:15

%S 121,484,91809,163216,255025,367236,499849,64128064,81162081,

%T 100200100,121242121,144288144,169338169,196392196,225450225,

%U 256512256,289578289,324648324,361722361,400800400,441882441,484968484,52910580529

%N Squares of the form u'v'w, where in decimal representation u=n^2, v=2*n^2 and w=n^2 possibly with a leading zero.

%C a(n) = A077431(n)^2.

%F a(n) = (n*(1 + 10^(1 + floor(log_10(2*n^2)))))^2.

%e n=42, n^2=1764 and 2*n^2=3528: a(42) = 1764'3528'1764 = 420042^2 = A077431(42)^2.

%Y Cf. A004216, A077430, A077431.

%K nonn,base,nice

%O 1,1

%A _Reinhard Zumkeller_, Nov 05 2002