A011532 Numbers that contain a 2.

2, 12, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 32, 42, 52, 62, 72, 82, 92, 102, 112, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 132, 142, 152, 162, 172, 182, 192, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• base
• easy

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
• Index entries for 10-automatic sequences.

Crossrefs

Numbers that contain a digit k: A011531 (k=1), A011533 (k=3), A011534 (k=4), A011535 (k=5), A011536 (k=6), A011537 (k=7), A011538 (k=8), A011539 (k=9), A011540 (k=0).

Programs

GAP

Filtered([1..220],n->2 in ListOfDigits(n)); # Muniru A Asiru, Feb 23 2019

Haskell

a011532 n = a011532_list !! (n-1)
a011532_list = filter ((elem '2') . show) [0..]
-- Reinhard Zumkeller, Apr 10 2015

Magma

[n: n in [0..500] | 2 in Intseq(n)]; // Vincenzo Librandi, Jan 11 2016

Mathematica

Select[Range[600] - 1, DigitCount[#, 10, 2]>0 &] (* Vincenzo Librandi, Jan 11 2016 *)

Formula

a(n) ~ n. - Charles R Greathouse IV, Feb 12 2017