A235717 Squares which have one or more occurrences of exactly two different digits.

16, 25, 36, 49, 64, 81, 100, 121, 144, 225, 400, 441, 484, 676, 900, 1444, 7744, 10000, 11881, 29929, 40000, 44944, 55225, 69696, 90000, 1000000, 4000000, 9000000, 9696996, 100000000, 400000000, 900000000, 6661661161, 10000000000, 40000000000, 90000000000

Offset

1,1

Comments

The first term having a repeated digit is 100.

This sequence is the same as A018885, except that A018885 has four additional leading terms.

Links

Table of n, a(n) for n=1..36.

Formula

a(n) = A016069(n)^2.

Example

69696 is in the sequence because 69696 = 264^2 and 69696 contains exactly two different digits: 6 and 9.

Prog

(PARI) s=[]; for(n=1, 10000, if(#vecsort(eval(Vec(Str(n^2))), , 8)==2, s=concat(s, n^2))); s

Crossrefs

Cf. A235718-A235724, A225218.

Sequence in context: A375116 A374934 A245371 * A368049 A319388 A291334

Adjacent sequences: A235714 A235715 A235716 * A235718 A235719 A235720

Keyword

nonn,base

Author

Colin Barker, Jan 15 2014

Status

approved