cp's OEIS Frontend

A102719 a(n) = a(n-1) + (sum of the last three digits of the sequence so far); a(0)=0; a(1)=1; a(2)=2 and a(n) < a(n+1).

%I A102719 #9 Mar 13 2025 14:46:26
%S A102719 0,1,2,5,13,22,29,42,57,71,86,101,103,107,115,122,127,137,148,161,169,
%T A102719 185,199,218,229,242,250,257,271,281,292,305,313,320,325,335,346,359,
%U A102719 376,392,406,416,427,440,448,464,478,497,517,530,538,554,568,587,607
%N A102719 a(n) = a(n-1) + (sum of the last three digits of the sequence so far); a(0)=0; a(1)=1; a(2)=2 and a(n) < a(n+1).
%H A102719 Alois P. Heinz, <a href="/A102719/b102719.txt">Table of n, a(n) for n = 0..10000</a>
%e A102719 86+(1+8+6) = 101.
%e A102719 101+(1+0+1) = 103.
%e A102719 103+(1+0+3) = 107.
%p A102719 a:= proc(n) option remember; local k, i; if n<2 then n elif n=2 then b(2):= [2,1,0]; 2 else k:= a(n-1) +add (i, i=b(n-1)); b(n):= [convert (k, base, 10)[], b(n-1)[]][1..3]; k fi end: seq (a(n), n=0..80); # _Alois P. Heinz_, Aug 13 2009
%t A102719 nxt[{a_,b_,c_}]:={b,c,c+Total[Take[Flatten[Join[IntegerDigits[a],IntegerDigits[b],IntegerDigits[c]]],-3]]}; NestList[nxt,{0,1,2},60][[;;,1]] (* _Harvey P. Dale_, Mar 13 2025 *)
%Y A102719 Cf. A102039.
%K A102719 base,easy,nonn
%O A102719 0,3
%A A102719 _Eric Angelini_, Feb 06 2005
%E A102719 Corrected and extended by _Alois P. Heinz_, Aug 13 2009