OFFSET
1,1
COMMENTS
a(19) > 10^13. - Jon E. Schoenfield, Dec 25 2008
a(21) > 10^14. - Giovanni Resta, Jul 27 2018
LINKS
Eric Weisstein's World of Mathematics, Square Number
EXAMPLE
From Jon E. Schoenfield, Dec 25 2008: (Start)
a(16) = 149071333335 = sqrt(22222262422274682222225);
a(17) = 1105537083332 = sqrt(1222212242622225512222224);
a(18) = 1489973900149 = sqrt(2220022223125222222222201). (End)
From Giovanni Resta, Jul 27 2018: (Start)
a(19) = 15106363633335 = sqrt(228202222222546222323222225);
a(20) = 47140462469223 = sqrt(2222223201812222222222223729). (End)
MATHEMATICA
a[n_] := Block[{k=1}, While[DigitCount[k^2, 10, 2] != n, k++]; k]; Array[a, 7] (* Giovanni Resta, Jul 27 2018 *)
CROSSREFS
KEYWORD
nonn,base,more
AUTHOR
Patrick De Geest, Mar 15 1999
EXTENSIONS
a(13)-a(15) from Max Alekseyev, Oct 20 2008, Nov 10 2008, Dec 05 2008
a(16)-a(18) from Jon E. Schoenfield, Dec 25 2008
a(19)-a(20) from Giovanni Resta, Jul 27 2018
STATUS
approved