A157908 Nonprimes whose digits are all square.

0, 1, 4, 9, 10, 14, 40, 44, 49, 90, 91, 94, 99, 100, 104, 110, 111, 114, 119, 140, 141, 144, 190, 194, 400, 404, 410, 411, 414, 440, 441, 444, 490, 494, 900, 901, 904, 909, 910, 914, 940, 944, 949, 990, 994, 999, 1000, 1001, 1004, 1010, 1011, 1014, 1040, 1041

Offset

1,3

Comments

Square digits are 0, 1, 4 or 9.

Links

Harvey P. Dale, Table of n, a(n) for n = 1..10000

Formula

a(n) = Theta(n^(log_4 10))

Mathematica

Select[FromDigits/@Tuples[{0, 1, 4, 9}, 4], !PrimeQ[#]&] (* Harvey P. Dale, Oct 14 2014 *)

Crossrefs

Cf. A000290, A141468.

Sequence in context: A054294 A198097 A358762 * A064973 A133764 A163643

Adjacent sequences: A157905 A157906 A157907 * A157909 A157910 A157911

Keyword

nonn,base

Author

Juri-Stepan Gerasimov, Mar 09 2009

Extensions

Formula from Charles R Greathouse IV, Mar 25 2010

Status

approved