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A062918
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Sum of the digit reversals of the first n natural numbers.
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5
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1, 3, 6, 10, 15, 21, 28, 36, 45, 46, 57, 78, 109, 150, 201, 262, 333, 414, 505, 507, 519, 541, 573, 615, 667, 729, 801, 883, 975, 978, 991, 1014, 1047, 1090, 1143, 1206, 1279, 1362, 1455, 1459, 1473, 1497, 1531, 1575, 1629, 1693, 1767, 1851, 1945, 1950, 1965
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OFFSET
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1,2
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COMMENTS
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a(n) = A000217(n) for n=1, 2, 3, 4, 5, 6, 7, 8, 9, 12, 86, 89, ...; checked up to 10^7. - Michel Marcus, Sep 15 2015; checked up to 2^32 ~ 4*10^9. - Kenny Lau, Aug 01 2017
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LINKS
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EXAMPLE
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a(12) = 78 as 1+2+3+4+5+6+7+8+9+R(10)+R(11)+R(12) = 1+2+3+4+5+6+7+8+9+01+11+21 = 78.
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MATHEMATICA
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Accumulate[Table[FromDigits[Reverse[IntegerDigits[n]]], {n, 1, 120}]] (* Enrique Pérez Herrero, Jun 01 2013 *)
Accumulate[IntegerReverse[Range[60]]] (* Harvey P. Dale, Dec 25 2021 *)
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PROG
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(PARI) { a=0; for (n=1, 1000, x=n; r=0; while (x>0, d=x-10*(x\10); x\=10; r=r*10 + d); write("b062918.txt", n, " ", a+=r) ) } \\ Harry J. Smith, Aug 12 2009
(PARI) a(n) = sum(k=1, n, eval(concat(Vecrev(Str(k))))); \\ Michel Marcus, Sep 15 2015
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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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More terms from Larry Reeves (larryr(AT)acm.org), Jul 05 2001
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STATUS
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approved
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