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A118836 Denominators of n-th convergent to continued fraction with semiprime terms. 2
1, 6, 55, 559, 1979, 400, 403, 8929, 224611, 1468634, 1475459, 50390831, 50609621, 482705812, 484571137, 22363019977, 157019195989, 157478504839, 157904409409, 143352242463851, 2301429052243, 143028260133641, 158315369959 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

Numerators are A118835. A118835/A118836 converges to semiprime continued fraction constant ~ 4.147. Fractions are 4/1, 25/6, 229/55, 2326/559, 8231/1979, 1663/400, 1675/403, 37102/8929, 933094/224611, 6099761/1468634, 6127061/1475459, 209220974/50390831, 210096134/50609621, 2003570923/482705812, 2011032223/484571137, 92798472958/22363019977, 651501535306/157019195989, 653338770706/157478504839, 655042388986/157904409409, 594467821319054/143352242463851, 9545375103547/2301429052243, 593171891998214/143028260133641, 656686231186/158315369959, 595688624302454/143657443209701, 11041298401059049/2662927412245381. These are to semiprimes as A001053 are to natural numbers. See also A105815 Decimal expansion of the semiprime nested radical.

LINKS

Eric Weisstein's World of Mathematics, Continued Fraction Constant.

FORMULA

a(n) = denominator of continued fraction [4; 6, 9, 10, 14, ... A001358(n)]. CONTINUANT transform of A001358.

EXAMPLE

a(1) = 1 = denominator of 4/1.

a(2) = 6 = denominator of 25/6 = 4+1/6.

a(3) = 55 = denominator of 229/55 = 4+1/(6+1/9).

a(4) = 559 = denominator of 2326/559 = 4+1/(6+1/9+(1/10)).

a(5) = 1979 = denominator of 8231/1979 = 4+1/(6+1/9+(1/10+(1/14))).

a(6) = 400 = denominator of 1663/400 = 4+1/(6+1/9+(1/10+(1/14+(1/15)))).

a(7) = 403 = denominator of 1675/403 = 4+1/(6+1/9+(1/10+(1/14+(1/15+(1/21))))).

a(8) = 8929 = denominator of 37102/8929 = 4+1/(6+1/9+(1/10+(1/14+(1/15+1/21+(1/22))))).

a(9) = 224611 = denominator of 933094/224611 = 4+1/(6+1/9+(1/10+(1/14+(1/15+(1/21+(1/22+ (1/25))))))).

a(20) = 158315369959 = denominator of 656686231186/158315369959 = 4+1/(6+1/9+(1/10+(1/14+(1/15+(1/21+(1/22+ (1/25+(1/26+(1/33+(1/34+(1/35+(1/38+(1/39+(1/46+(1/49+(1/51+(1/55+(1/57)))))))))))))))))).

CROSSREFS

Cf. A001358, A001040, A001053, A105815, A118835.

Sequence in context: A198855 A110431 A121661 * A079589 A006200 A151345

Adjacent sequences:  A118833 A118834 A118835 * A118837 A118838 A118839

KEYWORD

easy,frac,nonn

AUTHOR

Jonathan Vos Post (jvospost3(AT)gmail.com), May 01 2006

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Last modified February 15 17:46 EST 2012. Contains 205835 sequences.