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A047912 a(1) = 3; for n > 0, a(n+1) = a(n) * sum of digits of a(n). 10
3, 9, 81, 729, 13122, 118098, 3188646, 114791256, 4132485216, 148769467776, 10711401679872, 578415690713088, 41645929731342336, 2998506940656648192, 296852187125008171008, 24045027157125661851648 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Apart from the first term, the same as A047901. - R. J. Mathar, Oct 18 2008

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..250

FORMULA

a(n+1) = A057147(a(n)). - Reinhard Zumkeller, Mar 19 2014

MAPLE

P:=proc(n) local a, i, k, w; a:=3; print(a); for i from 1 by 1 to n do w:=0; k:=a; while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; a:=a*w; print(a); od; end: P(1000); # Paolo P. Lava, Apr 27 2007

MATHEMATICA

NestList[# Total[IntegerDigits[#]]&, 3, 20]  (* Harvey P. Dale, Mar 21 2011 *)

PROG

(Haskell)

a047912 n = a047912_list !! (n-1)

a047912_list = iterate a057147 3  -- Reinhard Zumkeller, Mar 19 2014

CROSSREFS

Cf. A047892 (start=2), A047897 (start=5), A047898 (start=6), A047899 (start=7), A047900 (start=8), A047901 (start=9), A047902 (start=11).

Sequence in context: A067623 A171557 A055156 * A078684 A121858 A215114

Adjacent sequences:  A047909 A047910 A047911 * A047913 A047914 A047915

KEYWORD

easy,nice,nonn,base

AUTHOR

Miklos SZABO (mike(AT)ludens.elte.hu)

STATUS

approved

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Last modified June 17 16:49 EDT 2021. Contains 345085 sequences. (Running on oeis4.)