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Search: id:A077487
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| A077487 |
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Squares which leave a square at every step if most significant digit and least significant digit are deleted until a one-digit or two-digit square is obtained. |
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+0
1
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| 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
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Sequence is infinite with nontrivial terms (10^(2k+1)+2)^2 and (2*10^(2k+1)+1)^2. - Ray Chandler (rayjchandler(AT)sbcglobal.net), Aug 03 2003
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EXAMPLE
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38416 is a member as 38416, 841, and 4 all are squares.
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PROGRAM
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(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^(k-2), c=d1*10^(k-1) + t1*10 + d2; if(issquare(c), listput(l, c); ); ); ); ); ); ); l
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CROSSREFS
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Cf. A077485, A077486.
Adjacent sequences: A077484 A077485 A077486 this_sequence A077488 A077489 A077490
Sequence in context: A025741 A030476 A077355 this_sequence A068864 A068854 A068867
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KEYWORD
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base,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Nov 07 2002
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EXTENSIONS
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Corrected and extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Aug 03 2003
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