A121040 Multiples of 20 containing a 20 in their decimal representation.

20, 120, 200, 220, 320, 420, 520, 620, 720, 820, 920, 1020, 1120, 1200, 1220, 1320, 1420, 1520, 1620, 1720, 1820, 1920, 2000, 2020, 2040, 2060, 2080, 2120, 2200, 2220, 2320, 2420, 2520, 2620, 2720, 2820, 2920, 3020, 3120, 3200, 3220, 3320, 3420, 3520

Offset: 1

Author

Reinhard Zumkeller, Jul 21 2006

Keywords

• nonn
• base
• easy

Comments

Not the same as A044352.

Links

• Index entries for 10-automatic sequences.

Crossrefs

Cf. A121041, A008602, A011531, A121022, A121023, A121024, A121025, A121026, A121027, A121028, A121029, A121030, A121031, A121032, A121033, A121034, A121035, A121036, A121037, A121038, A121039.

Programs

Mathematica

Select[20*Range[200],SequenceCount[IntegerDigits[#],{2,0}]>0&] (* The program uses the SequenceCount function from Mathematica version 10 *) (* Harvey P. Dale, Nov 27 2015 *)

PARI

is(n)=if(n%20, return(0)); while(n>19, if(n%100==20, return(1)); n\=10); 0 \\ Charles R Greathouse IV, Feb 12 2017

Formula

a(n) ~ 20n. - Charles R Greathouse IV, Feb 12 2017

Extensions

Corrected by T. D. Noe, Oct 25 2006