A190642 Numbers 3*n + 2 written in base 3.

2, 12, 22, 102, 112, 122, 202, 212, 222, 1002, 1012, 1022, 1102, 1112, 1122, 1202, 1212, 1222, 2002, 2012, 2022, 2102, 2112, 2122, 2202, 2212, 2222, 10002, 10012, 10022, 10102, 10112, 10122, 10202, 10212, 10222, 11002, 11012, 11022, 11102, 11112, 11122, 11202, 11212, 11222, 12002, 12012, 12022, 12102, 12112, 12122, 12202, 12212, 12222, 20002, 20012, 20022, 20102, 20112, 20122, 20202, 20212, 20222, 21002, 21012, 21022, 21102, 21112, 21122, 21202, 21212, 21222, 22002, 22012, 22022, 22102, 22112, 22122, 22202, 22212, 22222

Offset

0,1

Comments

In base 3 lunar arithmetic, sum of divisors of n = n (an analog of perfect numbers).

Links

Zhuorui He, Table of n, a(n) for n = 0..10000

D. Applegate, M. LeBrun, and N. J. A. Sloane, Dismal Arithmetic [Note: we have now changed the name from "dismal arithmetic" to "lunar arithmetic" - the old name was too depressing]

Index entries for sequences related to dismal (or lunar) arithmetic

Formula

a(n) = 10*A007089(n) + 2. - Zhuorui He, Nov 09 2025

Mathematica

FromDigits[IntegerDigits[#, 3]]&/@(3Range[0, 80]+2) (* Harvey P. Dale, Jun 07 2025 *)

Prog

(PARI) a(n)=fromdigits(digits(3 * n + 2, 3)) \\ Zhuorui He, Nov 09 2025

Crossrefs

Cf. A016789, A007089.

Sequence in context: A189330 A120672 A387396 * A108960 A111095 A073211

Adjacent sequences: A190639 A190640 A190641 * A190643 A190644 A190645

Keyword

nonn,base,easy

Author

N. J. A. Sloane, May 15 2011

Extensions

Offset changed by Zhuorui He, Nov 09 2025

Status

approved