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A219675
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Starting with a(0)=0, a(n) = 1 + the sum of the digital sums of a(0) through a(n-1).
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4
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0, 1, 2, 4, 8, 16, 23, 28, 38, 49, 62, 70, 77, 91, 101, 103, 107, 115, 122, 127, 137, 148, 161, 169, 185, 199, 218, 229, 242, 250, 257, 271, 281, 292, 305, 313, 320, 325, 335, 346, 359, 376, 392, 406, 416, 427, 440, 448, 464, 478, 497, 517, 530, 538, 554, 568
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graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,3
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COMMENTS
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LINKS
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FORMULA
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a(n) = Sum_{k=0..n-1} digsum(a(k)) + 1.
a(n) = a(n-1) + digsum(a(n-1)).
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EXAMPLE
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a(7) = 28 because (0+1+2+4+8+1+6+2+3) + 1 = 28.
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MATHEMATICA
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a219675[n_Integer] := Module[{f}, f[0] = 0; f[k_] := 1 + Sum[Plus @@ IntegerDigits[f[i]], {i, 0, k - 1}]; f[n]]; a219675/@Range[40] (* Michael De Vlieger, Nov 17 2014 *)
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PROG
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(PARI) lista(nn) = {v = vector(nn); for (n=2, nn, v[n] = 1 + sum(k=1, n-1, sumdigits(v[k])); ); v; } \\ Michel Marcus, Nov 17 2014
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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