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A193869 Smallest product of n distinct primes of the form n*k + 1. 5
2, 15, 1729, 32045, 60551711, 85276009, 52814801041129, 1312422595226609, 1130308388231798179, 4182230628909121261, 100166053986652515419641469, 1898732717895963155960377, 1011844196551535741726366525322443 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Also the row products of triangle A077316.
Note that a(3) = 1729 is known as the Hardy-Ramanujan number.
LINKS
EXAMPLE
a(1) = 2
a(2) = 3*5 = 15
a(3) = 7*13*19 = 1729
a(4) = 5*13*17*29 = 32045
a(5) = 11*31*41*61*71 = 60551711
a(6) = 7*13*19*31*37*43 = 85276009
MAPLE
Tj := proc(n, k) option remember: local j, p: if(k=0)then return 0:fi: for j from procname(n, k-1)+1 do if(isprime(n*j+1))then return j: fi: od: end: A193869 := proc(n) return mul(n*Tj(n, k)+1, k=1..n): end: seq(A193869(n), n=1..15); # Nathaniel Johnston, Sep 02 2011
CROSSREFS
Sequence in context: A068409 A359849 A096232 * A320768 A337799 A064171
KEYWORD
nonn
AUTHOR
Omar E. Pol, Sep 01 2011
EXTENSIONS
a(7)-a(14) from Nathaniel Johnston, Sep 02 2011
STATUS
approved

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Last modified July 13 08:08 EDT 2024. Contains 374274 sequences. (Running on oeis4.)