A106323 Smaller of number pair whose squares are reversals of each other, with no leading zeros allowed.

12, 13, 33, 102, 103, 112, 113, 122, 1002, 1003, 1011, 1012, 1013, 1021, 1022, 1031, 1102, 1103, 1112, 1113, 1121, 1122, 1202, 1212, 2012, 2022, 3168, 10002, 10003, 10011, 10012, 10013, 10021, 10022, 10031, 10102, 10103, 10111, 10112, 10113

Offset

1,1

Comments

For numbers whose squares are the reversal of a(n)^2, see A106324.

Links

Table of n, a(n) for n=1..40.

Example

33 is in the sequence because 33^2=1089 and we have 9801=99^2. Likewise,122^2=14884 and we have 48841=221^2.

Prog

(PARI) isok(n) = {if (n % 10 == 0, return (0)); d = digits(n^2, 10); m = sum(k=0, #d-1, d[k+1]*10^(k)); if (! issquare(m), return (0)); return (n < sqrtint(m)); } \\ Michel Marcus, Jul 28 2013

Crossrefs

Cf. A035090; A035123.

Half of A035123.

Sequence in context: A022317 A125998 A307279 * A177796 A342942 A322462

Adjacent sequences: A106320 A106321 A106322 * A106324 A106325 A106326

Keyword

base,nonn

Author

Lekraj Beedassy, Apr 29 2005

Extensions

Corrected and extended by Joshua Zucker, May 12 2006

Status

approved