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A248204
Middle values in trios of products of 5 distinct primes.
8
16467034, 18185870, 21134554, 21374354, 21871366, 22247554, 22412534, 22721586, 24845314, 25118094, 25228930, 25435334, 25596934, 26217246, 27140114, 29218630, 29752346, 30323734, 30563246, 31943066, 32663266, 33367894, 36055046, 38269022, 39738062, 40547066
OFFSET
1,1
COMMENTS
A subsequence of A066509 and offset by 1 from A192203.
LINKS
FORMULA
a(n) = A192203(n) + 1.
EXAMPLE
16467033=3*11*17*149*197,
16467034=2*19*23*83*227, and
16467035=5*13*37*41*167,
with no smaller similar trio. So a(1)=16467034. [Corrected by James G. Merickel, Jul 23 2015]
PROG
(PARI)
{
\\ This program checks all consecutives with elements not divisible \\
\\ by the squares of 2 or 3. More efficiency is required if enormous \\
\\ numbers of terms are sought and for the analog sequences beyond \\
\\ 6 prime factors. The start value is A093550(5). If a start other \\
\\ than this is chosen, one must be sure that (one of) s or u is \\
\\ adjusted if it needs to be. \\
n=16467034; s=[8, 4, 4, 4, 8, 8]; u=1;
while(1,
if(issquarefree(n) && issquarefree(n-1) && issquarefree(n+1) && omega(n)==5 && omega(n-1)==5 && omega(n+1)==5, print1(n" "));
n+=s[u];
if(u==6, u=1, u++)
)
} \\ James G. Merickel, Jul 23 2015
KEYWORD
nonn
AUTHOR
James G. Merickel, Oct 28 2014
STATUS
approved