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A009470 a(n) is the concatenation of n and 8n. 9
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified October 23 21:57 EDT 2019. Contains 328373 sequences. (Running on oeis4.)