A121022 Even numbers containing a 2 in their decimal representation.

2, 12, 20, 22, 24, 26, 28, 32, 42, 52, 62, 72, 82, 92, 102, 112, 120, 122, 124, 126, 128, 132, 142, 152, 162, 172, 182, 192, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226, 228, 230, 232, 234, 236, 238, 240, 242, 244, 246, 248, 250, 252

Offset

1,1

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Seong Ju Kim, R. Stees, L. Taalman, Sequences of Spiral Knot Determinants, Journal of Integer Sequences, Vol. 19 (2016), # 16.1.4.

Ryan Stees, Sequences of Spiral Knot Determinants, Senior Honors Projects, Paper 84, James Madison Univ., May 2016.

Index entries for 10-automatic sequences.

Formula

a(n) ~ 2n. - Charles R Greathouse IV, Mar 30 2022

Mathematica

Select[2*Range[200], DigitCount[#, 10, 2]>0&] (* Harvey P. Dale, Nov 04 2013 *)

Prog

(Haskell)
a121022 n = a121022_list !! (n-1)
a121022_list = filter (('2' `elem`) . show) [0, 2 ..]
-- Reinhard Zumkeller, Nov 08 2013
(PARI) is(n) = n%2==0 && setsearch(vecsort(digits(n)), 2) \\ Felix Fröhlich, Nov 22 2020

Crossrefs

Intersection of A005843 and A011532.

Cf. A121041, A011531, A121023, A121024, A121025, A121026, A121027, A121028, A121029, A121030, A121031, A121032, A121033, A121034, A121035, A121036, A121037, A121038, A121039, A121040.

Sequence in context: A043497 A051804 A352262 * A277589 A069164 A067762

Adjacent sequences: A121019 A121020 A121021 * A121023 A121024 A121025

Keyword

nonn,base,easy

Author

Reinhard Zumkeller, Jul 21 2006

Status

approved