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A050214 Product((d+n/d): d divides n and d^2<=n); a(1)=1. 0
1, 3, 4, 20, 6, 35, 8, 54, 60, 77, 12, 728, 14, 135, 128, 1360, 18, 1881, 20, 2268, 220, 299, 24, 38500, 260, 405, 336, 5104, 30, 75361, 32, 7128, 476, 665, 432, 1731600, 38, 819, 640, 164164, 42, 218569, 44, 16200, 11592, 1175, 48, 5422144, 700, 20655, 1040 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n)=n+1 iff n is prime.

LINKS

Table of n, a(n) for n=1..51.

EXAMPLE

a(12)=(1+12)*(2+6)*(3+4)=13*8*7=728.

MATHEMATICA

pdn[n_]:=Module[{d=Select[Divisors[n], #^2<=n&]}, Times@@ (Total/@ ({#, n/#}&/@d ))]; Join[{1}, Array[pdn, 60, 2]] (* Harvey P. Dale, May 03 2013 *)

CROSSREFS

Sequence in context: A041989 A196198 A041561 * A256605 A237884 A256532

Adjacent sequences:  A050211 A050212 A050213 * A050215 A050216 A050217

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, May 08 2003

EXTENSIONS

Corrected and extended by Harvey P. Dale, May 03 2013

STATUS

approved

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Last modified August 8 05:50 EDT 2020. Contains 336290 sequences. (Running on oeis4.)