

A077487


Squares which leave a square at every step if most significant digit and least significant digit are deleted until a onedigit or twodigit square is obtained.


0



1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 144, 196, 400, 441, 841, 900, 1369, 3364, 4096, 5041, 8649, 10000, 10816, 11449, 20164, 38416, 40000, 61009, 64009, 90000, 1000000, 1004004, 3013696, 3108169, 4000000, 4004001, 9000000, 100000000
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OFFSET

1,2


COMMENTS

Sequence is infinite with nontrivial terms (10^(2k+1)+2)^2 and (2*10^(2k+1)+1)^2.  Ray Chandler, Aug 03 2003


LINKS

Table of n, a(n) for n=1..38.


EXAMPLE

38416 is a member as 38416, 841 and 4 all are squares.


PROG

(PARI) l=listcreate(1000); for(n=0, 9, listput(l, n^2)); for(k=3, 50, for(d1=1, 9, for(n=1, length(l), for(d2=0, 9, t1=l[n]; if(t1<10^(k2), c=d1*10^(k1) + t1*10 + d2; if(issquare(c), listput(l, c); ); ); ); ); ); ); l


CROSSREFS

Cf. A077485, A077486.
Sequence in context: A326707 A030476 A077355 * A179334 A068864 A068854
Adjacent sequences: A077484 A077485 A077486 * A077488 A077489 A077490


KEYWORD

base,nonn


AUTHOR

Amarnath Murthy, Nov 07 2002


EXTENSIONS

Corrected and extended by Ray Chandler, Aug 03 2003


STATUS

approved



