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 A281919 8th-power analog of Keith numbers. 9
 1, 30, 46, 54, 63, 207, 394, 693, 694, 718, 20196, 42664, 80051, 90135, 91447, 93136, 207846, 324121, 361401, 421609, 797607, 802702, 882227, 1531788, 1788757, 1789643, 4028916, 4176711, 6692664, 15643794, 31794346, 65335545, 140005632, 144311385, 153364253 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Like Keith numbers but starting from n^8 digits to reach n. Consider the digits of n^8. Take their sum and repeat the process deleting the first addend and adding the previous sum. The sequence lists the numbers that after some number of iterations reach a sum equal to n. LINKS Giovanni Resta, Table of n, a(n) for n = 1..40 FORMULA 207^8 = 3371031134626313601: 3 + 3 + 7 + 1 + 0 + 3 + 1 + 1 + 3 + 4 + 6 + 2 + 6 + 3 + 1 + 3 + 6 + 0 + 1 = 54; 3 + 7 + 1 + 0 + 3 + 1 + 1 + 3 + 4 + 6 + 2 + 6 + 3 + 1 + 3 + 6 + 0 + 1 + 54 = 105; 7 + 1 + 0 + 3 + 1 + 1 + 3 + 4 + 6 + 2 + 6 + 3 + 1 + 3 + 6 + 0 + 1 + 54 + 105 = 207. MAPLE with(numtheory): P:=proc(q, h, w) local a, b, k, t, v; global n; v:=array(1..h); for n from 1 to q do b:=n^w; a:=[]; for k from 1 to ilog10(b)+1 do a:=[(b mod 10), op(a)]; b:=trunc(b/10); od; for k from 1 to nops(a) do v[k]:=a[k]; od; b:=ilog10(n^w)+1; t:=nops(a)+1; v[t]:=add(v[k], k=1..b); while v[t]

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Last modified July 22 06:07 EDT 2024. Contains 374481 sequences. (Running on oeis4.)