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”).

A176813
Numbers n such that 3*A077800(2n-1)<p and p+2<3*A077800(2n) where A077800 is list of twin primes {p,p+2}.
0
1, 2, 7, 18, 60, 82, 149, 228, 229, 268, 325, 340, 372, 479, 508, 510, 515, 518, 619, 622, 710, 743, 790, 892, 910, 955, 998, 1020, 1158, 1184, 1215, 1266, 1310, 1363, 1431, 1478, 1567, 1885, 1921, 1979, 2066, 2316, 2476, 2541, 2688, 2704, 2781, 2798, 2809
OFFSET
1,2
COMMENTS
Indices n of lower twin primes A001359(n) such that both members of some twin prime pair (p,p+2) are inside the open interval (3*A001359(n),3*A006512(n)). [R. J. Mathar, May 10 2010]
EXAMPLE
a(1)=1 because 3*A077800(2*1-1)=9<11 and 11+2<3*A077800(2*1)=15;
a(2)=2 because 3*A077800(2*2-1)=15<17 and 17+2<3*A077800(2*2)=21;
a(3)=7 because 3*A077800(2*7-1)=177<179 and 179+2<3*A077800(2*7)=183;
a(4)=18 because 3*A077800(2*18-1)=807<809 and 809+2<3*A077800(2*18)=813;
a(5)=60 because 3*A077800(2*60-1)=5847<5849 and 5849+2<3*A077800(2*60)=5853.
CROSSREFS
Sequence in context: A291255 A294004 A214836 * A000988 A185308 A002214
KEYWORD
nonn
AUTHOR
EXTENSIONS
Extended beyond 60 by R. J. Mathar, May 10 2010
STATUS
approved