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A304085
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Divisor-or-multiple permutation of natural numbers: a(n) = A052330(A304083(n)).
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6
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1, 2, 6, 3, 24, 12, 4, 8, 120, 60, 20, 5, 40, 10, 30, 15, 840, 420, 140, 35, 7, 280, 70, 14, 210, 105, 21, 168, 84, 28, 56, 7560, 42, 1890, 945, 315, 63, 9, 3780, 1260, 252, 36, 2520, 630, 126, 18, 1512, 756, 189, 27, 378, 54, 1080, 540, 180, 45, 360, 90, 270, 135, 83160, 504, 72, 216, 108, 41580, 13860, 3465, 693, 99, 11, 27720, 6930, 1386, 198, 22, 20790
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OFFSET
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0,2
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COMMENTS
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Each a(n) is always either a divisor or a multiple of a(n+1).
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LINKS
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FORMULA
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PROG
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(PARI)
up_to_e = 16; \\ Good for computing up to n = (2^16)-1
v050376 = vector(up_to_e);
ispow2(n) = (n && !bitand(n, n-1));
i = 0; for(n=1, oo, if(ispow2(isprimepower(n)), i++; v050376[i] = n); if(i == up_to_e, break));
A052330(n) = { my(p=1, i=1); while(n>0, if(n%2, p *= A050376(i)); i++; n >>= 1); (p); };
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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