A077512 Largest n-digit square beginning with n.

1, 25, 361, 4900, 59536, 698896, 7997584, 89984196, 999950884, 1099983556, 11999887936, 129999908025, 1399997736225, 14999997318289, 159999983792100, 1699999978875136, 17999999825590084, 189999999691331236, 1999999998944727844, 20999999991239581636, 219999999994324356676, 2299999999987799844289

Offset

1,2

Links

Table of n, a(n) for n=1..22.

Formula

a(n) = (ceiling(sqrt((n+1)*10^(n-floor(log_10(10*n))))) - 1)^2 = (ceiling(sqrt((n+1)*10^(n-A055642(n)))) - 1)^2. - Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Nov 16 2002

Mathematica

f[n_] := Module[{idn=IntegerDigits[n]}, FromDigits[Join[idn, Table[9, {n-Length[idn]}]]]]; Table[Floor[Sqrt[f[i]]]^2, {i, 30}]

Prog

(PARI) a(n) = if(n==1, return(1)); my(d=digits(n+1)); d=concat(d, vector(n-#digits(n))); floor(sqrt(fromdigits(d)-1))^2 \\ David A. Corneth, Jun 08 2019

Crossrefs

Sequence in context: A125460 A188487 A306083 * A261972 A197678 A197536

Adjacent sequences: A077509 A077510 A077511 * A077513 A077514 A077515

Keyword

base,nonn

Author

Amarnath Murthy, Nov 08 2002

Extensions

More terms from Harvey P. Dale and Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Nov 14 2002

a(1) prepended and more terms from David A. Corneth, Jun 08 2019

Status

approved