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A095234
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a(1) = 1, a(n) = n+a(n-1) if n does not divide a(n-1), else a(n) = n*a(n-1).
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2
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1, 3, 9, 13, 18, 108, 115, 123, 132, 142, 153, 165, 178, 192, 207, 223, 240, 258, 277, 297, 318, 340, 363, 387, 412, 438, 465, 493, 14297, 14327, 14358, 14390, 14423, 14457, 14492, 14528, 14565, 14603, 14642, 14682, 14723, 14765, 14808, 14852
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OFFSET
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1,2
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COMMENTS
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Where a(n) <> a(n-1)+n: 3, 6, 29, 116 and 348 and no others < 2*10^6. - Robert G. Wilson v, Jun 18 2004
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LINKS
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EXAMPLE
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a(29) = a(28)*29 = 493*29 = 14297 since 29 divides a(28) = 493 = 17*29.
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MATHEMATICA
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a[1] = 1; a[n_] := a[n] = If[Mod[a[n - 1], n] == 0, n*a[n - 1], a[n - 1] + n]
nxt[{n_, a_}]:={n+1, If[Divisible[a, n+1], a(n+1), a+n+1]}; NestList[nxt, {1, 1}, 50][[All, 2]] (* Harvey P. Dale, Jan 14 2017 *)
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PROG
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(PARI) m=44; print1(a=1, ", "); for(n=2, m, print1(a=if(a%n>0, n+a, n*a), ", ")) \\ Klaus Brockhaus, Jun 18 2004
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CROSSREFS
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Cf. A096155 for those n that divide a(n-1).
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KEYWORD
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easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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