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A342012
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Primorial deflation of the n-th colossally abundant number: the unique integer k such that A108951(k) = A004490(n).
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7
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2, 3, 6, 10, 20, 30, 42, 84, 132, 156, 312, 468, 780, 1020, 1140, 1380, 2760, 3480, 3720, 5208, 7812, 9324, 10332, 10836, 21672, 23688, 26712, 29736, 49560, 51240, 56280, 59640, 61320, 96360, 104280, 208560, 219120, 328680, 352440, 384120, 453960, 472680, 482040, 500760, 510120, 528840, 594360, 613080, 641160, 650520, 1301040
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OFFSET
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1,1
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COMMENTS
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In contrast to A329902, this sequence is monotonic, because each term is obtained from the previous, either by multiplying it by 2, or by "bumping" one [or hypothetically: two] of its prime factors one step up (i.e., replacing it with the next larger prime), and both operations are guaranteed to make the number larger.
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LINKS
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FORMULA
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PROG
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(PARI)
v073751 = readvec("b073751_to.txt");
A004490list(v073751) = { my(v=vector(#v073751)); v[1] = 2; for(n=2, #v, v[n] = v073751[n]*v[n-1]); (v); };
v004490 = A004490list(v073751);
A064989(n) = {my(f); f = factor(n); if((n>1 && f[1, 1]==2), f[1, 2] = 0); for (i=1, #f~, f[i, 1] = precprime(f[i, 1]-1)); factorback(f)};
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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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