[go: up one dir, main page]

login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A088328 revision #8

A088328
Table read by rows where row n contains lower twin primes of the form k*A002110(n)-1 in the range 0 < k < A006094(n+1).
3
3, 5, 11, 17, 5, 11, 17, 29, 41, 59, 71, 101, 107, 137, 149, 179, 191, 197, 29, 59, 149, 179, 239, 269, 419, 569, 599, 659, 809, 1019, 1049, 1229, 1319, 1619, 1949, 2129, 419, 1049, 2309, 2729, 3359, 5879, 6089, 6299, 7349, 7559, 8819, 9239, 10499, 10709
OFFSET
1,1
COMMENTS
Some of the values k*primorial(n)-1 generated by k in the range 1 to prime(n+1)*prime(n+2)-1 are not lower twin primes, A001359, so the list of k that produces the n-th row of the irregular table, as shown in A088329, is not a list of necessarily consecutive integers.
If n>2 the count of k values is near or greater than 4*log(4*p(n+1)); is this related to a proof of the infinity of twin prime pairs?
EXAMPLE
2*2 -1 = 3, k=2, n=1
3*2 -1 = 5, k=3, n=1
6*2 -1 = 11, k=6, n=1
9*2 -1 = 17, k=9, n=1
The first three rows are:
3,5,11,17; generated by k=2, 3, 6, 9
5,11,17,29,41,59,71,101,107,137,149,179,191,197;
29,59,149,179,239,269,419,569,599,659,809,1019,1049,1229,1289,1319,1619,1949,2129;
MAPLE
isA001359 := proc(n) option remember ; return isprime(n) and isprime(n+2) ; end:
A002110 := proc(n) local i ; if n = 0 then 1; else mul(ithprime(i), i=1..n) ; end if; end proc:
A006094 := proc(n) return ithprime(n)*ithprime(n+1) ; end proc:
A088328 := proc(n, k) option remember; for j from 1 to A006094(n+1)-1 do a := j*A002110(n)-1 ; if isA001359(a) and k =1 then return a ; elif isA001359(a) and a > procname(n, k-1) then return a ; end if; end do; return -1 ; end proc:
for n from 1 to 10 do for k from 1 do T := A088328(n, k) ; if T < 0 then break; else printf("%d, ", T) ; end if; end do; printf("\n") ; od: # R. J. Mathar, Oct 30 2009
CROSSREFS
Sequence in context: A327043 A006169 A323582 * A102643 A279767 A125631
KEYWORD
nonn,tabf
AUTHOR
Pierre CAMI, Nov 06 2003
EXTENSIONS
Edited by R. J. Mathar, Oct 30 2009
STATUS
editing