A062118 Numbers k such that k^2 has k as its middle digits.
1, 50, 60, 250, 3792, 7600, 376000, 495475, 625000, 971582, 66952741, 93760000, 177656344, 3199268655, 9062500000, 10937600000, 788138178328, 860628177919, 890625000000, 2291665833333, 2780225311054, 2890625000000, 71093760000000, 128906250000000
Offset: 1
Examples
a(5)=3792 because 3792^2 = 14379264 has 3792 as its middle digits.
References
- Computed by Robert Israel.
Crossrefs
k^2 is given in A062120.
Programs
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Mathematica
Do[ If[ StringPosition[ ToString[n^2], ToString[n]] [[1, 1]] == (Ceiling[ Log[10, n^2] ] - Ceiling[ Log[10, n] ])/2 + 1, Print[n] ], {n, 1, 10^9} ]
Extensions
Corrected and extended by Robert G. Wilson v, Aug 08 2001
a(15)-a(24) from Giovanni Resta, Jul 29 2013
Comments