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 A077485 a(1) = 1, then smallest n-digit square which leaves a square at every step if most significant digit and least significant digit are deleted until a one-or two-digit digit square is obtained. a(2n) = 0 if no such square exists. a(2n+1) = 10^2n only if no nontrivial candidate exists. 2
 1, 16, 144, 1369, 10816, 0, 1004004, 0, 100000000, 0, 10000400004, 0, 1000000000000, 0, 100000040000004, 0, 10000000000000000, 0, 1000000004000000004, 0, 100000000000000000000, 0, 10000000000400000000004 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS FORMULA Beginning with term a(6) the following pattern applies: a(4k)=0; a(4k+1)=10^4k=(10^2k)^2; a(4k+2)=0; a(4k+3)=(10^(2k+1)+2)^2. - Ray Chandler, Aug 03 2003 EXAMPLE a(3) = 144 as 144 and 4 are both squares. a(4) = 1369 as 1369 and 36 are both squares. CROSSREFS Cf. A077486. Sequence in context: A282524 A287168 A155663 * A131705 A203538 A076029 Adjacent sequences:  A077482 A077483 A077484 * A077486 A077487 A077488 KEYWORD base,nonn AUTHOR Amarnath Murthy, Nov 07 2002 EXTENSIONS Corrected and extended by Ray Chandler, Aug 03 2003 STATUS approved

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Last modified December 3 21:17 EST 2021. Contains 349468 sequences. (Running on oeis4.)