

A084228


a(1)=1, a(2)=2; thereafter a(n) = sum of digits of (a(1)+a(2)+a(3)+...+a(n1)).


4



1, 2, 3, 6, 3, 6, 3, 6, 3, 6, 12, 6, 12, 15, 12, 15, 3, 6, 3, 6, 12, 6, 12, 15, 12, 15, 3, 6, 3, 6, 12, 6, 12, 15, 12, 15, 12, 6, 12, 6, 12, 15, 12, 15, 12, 15, 12, 6, 12, 15, 12, 15, 12, 15, 12, 15, 12, 15, 12, 15, 21, 15, 12, 15, 12, 15, 21, 24, 12, 15, 12, 15, 21, 24, 12, 15, 21, 15
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OFFSET

1,2


COMMENTS

a(n) == 3 or 6 (mod 9) n>2.
a(n) = 3 for n in A084229.
a(n) = 6 for n = 4, 6, 8, 10, 12, 18, 20, 22, 28, 30, 32, 38, 40, 48, 86, 88, 90, 96, 98, 100, 106, 108, 116, 160, 162, 168, 170, 178, ..., 17630.  Robert G. Wilson v, Jun 27 2014


LINKS

Robert G. Wilson v, Table of n, a(n) for n = 1..10000
Index entries for Colombian or self numbers and related sequences


MATHEMATICA

a[1] = 1; a[2] = 2; a[n_] := a[n] = Sum[ Total@ IntegerDigits@ a@ i, {i, n  1}]; Array[ Total@ IntegerDigits@ a@# &, 78] (* Robert G. Wilson v, Jun 27 2014 *)


PROG

(PARI) // sumdig(n)=sum(k=0, ceil(log(n)/log(10)), floor(n/10^k)%10) // an=vector(10000); a(n)=if(n<0, 0, an[n]) // an[1]=1; an[2]=2; for(n=3, 300, an[n]=sumdig(sum(k=1, n1, a(k)))) //
(Haskell)
a084228 n = a084228_list !! (n1)
a084228_list = 1 : 2 : f 3 where
f x = y : f (x + y) where y = a007953 x
 Reinhard Zumkeller, Nov 13 2014


CROSSREFS

Cf. A065075, A016052, A230286, A230287, A004207, A084229.
Sequence in context: A216059 A261814 A240965 * A328571 A275733 A245499
Adjacent sequences: A084225 A084226 A084227 * A084229 A084230 A084231


KEYWORD

base,nonn


AUTHOR

Benoit Cloitre, Jun 21 2003


STATUS

approved



