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A140389 Composites of the form ((3*x*y-y-6)/(3*x+1), where x=composite and y=composite. 0
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified July 20 16:34 EDT 2019. Contains 325185 sequences. (Running on oeis4.)