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 A282767 n/3 analog of Keith numbers. 2
 45, 609, 1218, 1827, 3213, 21309, 28206, 29319, 31917, 39333, 47337, 78666, 102090, 117999, 204180, 406437, 302867592, 4507146801, 5440407522 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Like Keith numbers but starting from n/3 digits to reach n. Consider the digits of n/3. Take their sum and repeat the process deleting the first addend and adding the previous sum. The sequence lists the numbers that after some iterations reach a sum equal to themselves. If it exists, a(20) > 10^12. - Lars Blomberg Mar 13 2017 LINKS EXAMPLE 609/3 = 203: 2 + 0 + 3 = 5; 0 + 3 + 5 = 8; 3 + 5 + 8 = 16; 5 + 8 + 16 = 29; 8 + 16 + 29 = 53; 16 + 29 + 53 = 98; 29 + 53 + 98 = 180; 53 + 98 + 180 = 331; 98 + 180 + 331 = 609. MAPLE with(numtheory): P:=proc(q, h, w) local a, b, k, n, t, v; v:=array(1..h); for n from 1/w by 1/w to q do a:=w*n; b:=ilog10(a)+1; if b>1 then for k from 1 to b do v[b-k+1]:=(a mod 10); a:=trunc(a/10); od; t:=b+1; v[t]:=add(v[k], k=1..b); while v[t]

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Last modified May 10 05:05 EDT 2021. Contains 343748 sequences. (Running on oeis4.)