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A065808 Square of n has a smaller square as its final digits. 2
7, 8, 9, 10, 11, 12, 13, 15, 17, 18, 19, 20, 21, 22, 23, 25, 27, 28, 29, 30, 31, 32, 33, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 67, 68, 69, 70, 71, 72, 73, 75, 77, 78, 79, 80, 81, 82, 83, 85, 87, 88 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Includes all n >= 7 not == 4 or 6 (mod 10). - Robert Israel, Oct 24 2017

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

filter:= n ->

  ormap(t -> issqr(n^2 mod 10^t), [$1..ilog10(n^2)]):

select(filter, [$1..100]); # Robert Israel, Oct 24 2017

MATHEMATICA

ds[n_] := NestWhileList[FromDigits[Rest[IntegerDigits[#]]] &, n, # > 9 &]; Select[Range[4, 88], Or @@ IntegerQ /@ Sqrt[Rest[ds[#^2]]] &] (* Jayanta Basu, Jul 10 2013 *)

PROG

(PARI): a065808(m) = local(k, a, b, d, j, n, r); for(k=1, m, a=length(Str(n))-1; b=1; j=1; n=k^2; while(b, d=divrem(n, 10^j); if(d[1]>0&&issquare(d[2]), b=0; issquare(n, &r); print1(r, ", "), if(j<a, j++, b=0)))) a065808(100)

CROSSREFS

A065807 gives the corresponding squares.

Cf. A065690, A050635, A050637, A050639, A065777, A065780, A065783, A065786, A065789, A065792.

Sequence in context: A162787 A182308 A023388 * A250046 A062947 A194345

Adjacent sequences:  A065805 A065806 A065807 * A065809 A065810 A065811

KEYWORD

base,easy,nonn

AUTHOR

Klaus Brockhaus, Nov 22 2001

EXTENSIONS

Offset changed to 1 by Robert Israel, Oct 24 2017

STATUS

approved

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Last modified September 19 06:56 EDT 2021. Contains 347551 sequences. (Running on oeis4.)