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A114434 To obtain a(n), write the n-th composite number as a product of primes, add 1 to each prime and multiply. 2
9, 12, 27, 16, 18, 36, 24, 24, 81, 48, 54, 32, 36, 108, 36, 42, 64, 72, 72, 243, 48, 54, 48, 144, 60, 56, 162, 96, 108, 96, 72, 324, 64, 108, 72, 126, 192, 72, 216, 80, 90, 216, 96, 128, 729, 84, 144, 162, 96, 144, 432, 114, 144, 180, 96, 168, 486, 256 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A003959(A002808(n)). - Michel Marcus, Oct 22 2014

MAPLE

b:= proc(n) option remember; local k;

      for k from 1+`if`(n=1, 3, b(n-1))

      while isprime(k) do od; k

    end:

a:= n-> mul((i[1]+1)^i[2], i=ifactors(b(n))[2]):

seq(a(n), n=1..100);  # Alois P. Heinz, Oct 23 2014

PROG

(PARI) lista(nn) = {forcomposite(c=2, nn, f = factor(c); print1(prod(i=1, #f~, (f[i, 1]+1)^f[i, 2]), ", "); ); } \\ Michel Marcus, Jun 26 2013

CROSSREFS

Cf. A002808, A003959, A249140.

Sequence in context: A057577 A014766 A182877 * A105704 A216192 A195162

Adjacent sequences:  A114431 A114432 A114433 * A114435 A114436 A114437

KEYWORD

nonn

AUTHOR

Ben Paul Thurston, May 06 2007

EXTENSIONS

More terms from Michel Marcus, Jun 26 2013

STATUS

approved

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Last modified May 25 11:04 EDT 2019. Contains 323539 sequences. (Running on oeis4.)