A140389 Composites of the form (3*x*y-y-6)/(3*x+1), where x=composite and y=composite.

91, 115, 121, 205, 295, 301, 319, 325, 391, 403, 451, 481, 511, 535, 667, 685, 701, 721, 745, 763, 775, 799, 841, 847, 865, 871, 895, 913, 931, 955, 961, 985, 1003, 1075, 1111, 1135, 1195, 1207, 1243, 1267, 1309, 1333, 1339, 1345, 1351, 1375, 1387, 1411, 1417

Offset

1,1

Comments

x=c(i)=i-th composite and y=c(j)=j-th composite.

Links

Table of n, a(n) for n=1..49.

Example

If x=16 and y=95, then
(3*16*95-95-6)/(3*16+1)=4459/49=91=a(1).
If x=20 and y=119, then (3*20*119-119-6)/(3*20+1)=7015/61=115=a(2).
If x=21 and y=125, then (3*21*125-125-6)/(3*21+1)=7744/64=121=a(3).
If x=35 and y=209, then (3*35*209-209-6)/(3*35+1)=21730/106=205=a(4).
If x=50 and y=299, then (3*50*299-299-6)/(3*50+1)=44545/151=295=a(5).
If x=51 and y=305, then (3*51*305-305-6)/(3*51+1)=46354/154=301=a(6),
etc.

Crossrefs

Cf. A002808, A000040.

Sequence in context: A224981 A261260 A161945 * A236845 A157345 A092125

Adjacent sequences: A140386 A140387 A140388 * A140390 A140391 A140392

Keyword

nonn

Author

Juri-Stepan Gerasimov, Aug 28 2008

Status

approved