A009470 a(n) is the concatenation of n and 8n.

18, 216, 324, 432, 540, 648, 756, 864, 972, 1080, 1188, 1296, 13104, 14112, 15120, 16128, 17136, 18144, 19152, 20160, 21168, 22176, 23184, 24192, 25200, 26208, 27216, 28224, 29232, 30240, 31248, 32256, 33264, 34272, 35280, 36288, 37296, 38304, 39312

Offset

1,1

Comments

All terms are divisible by 9. - Michel Marcus, Sep 21 2015

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Mathematica

nxt[n_]:=Module[{idn=IntegerDigits[n], idn8=IntegerDigits[8n]}, FromDigits[Join[idn, idn8]]]; Array[nxt, 100] (* Vincenzo Librandi, Feb 04 2014 *)

Prog

(Magma) [Seqint(Intseq(8*n) cat Intseq(n)): n in [1..50]]; // Vincenzo Librandi, Feb 04 2014
(PARI) a(n) = eval(Str(n, 8*n)); \\ Michel Marcus, Sep 21 2015

Crossrefs

Cf. concatenation of n and k*n: A020338 (k=1), A019550 (k=2), A019551 (k=3), A019552 (k=4), A019553 (k=5), A009440 (k=6), A009441 (k=7), this sequence (k=8), A009474 (k=9).

Sequence in context: A021764 A059357 A324638 * A111991 A081136 A101188

Adjacent sequences: A009467 A009468 A009469 * A009471 A009472 A009473

Keyword

nonn,base,less,easy

Author

David W. Wilson

Status

approved