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A020696 Let a,b,c,...k be all divisors of n; a(n) = (a+1)*(b+1)*...*(k+1). 5
2, 6, 8, 30, 12, 168, 16, 270, 80, 396, 24, 10920, 28, 720, 768, 4590, 36, 31920, 40, 41580, 1408, 1656, 48, 2457000, 312, 2268, 2240, 104400, 60, 5499648, 64, 151470, 3264, 3780, 3456, 76767600, 76, 4680, 4480, 15343020, 84, 19071360, 88 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(p) = 2(p+1), a(p^2) = 2(p+1)(p^2+1) for primes p.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = Product(A027750(n,k) + 1: k = 1..A000005(n)). - Reinhard Zumkeller, Mar 28 2015

MATHEMATICA

Table[Times @@ (Divisors[n] + 1), {n, 43}] (* Ivan Neretin, May 27 2015 *)

PROG

(PARI) a(n) = {d = divisors(n); return (prod(i=1, #d, d[i]+1)); } \\ Michel Marcus, Jun 12 2013

(Haskell)

a020696 = product . map (+ 1) . a027750_row'

-- Reinhard Zumkeller, Mar 28 2015

CROSSREFS

Cf. A027750, A000005, A003959.

Cf. A057643 (LCM instead of product).

Cf. A299436 (exp).

Sequence in context: A210737 A140539 A056188 * A290249 A321471 A216762

Adjacent sequences:  A020693 A020694 A020695 * A020697 A020698 A020699

KEYWORD

nonn,easy

AUTHOR

Amarnath Murthy, Jun 01 2003

EXTENSIONS

Edited by Don Reble, Jun 05 2003

STATUS

approved

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Last modified April 23 22:17 EDT 2019. Contains 322388 sequences. (Running on oeis4.)