cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Previous Showing 11-18 of 18 results.

A376053 Numerator of the sum S(n) defined in A376052.

Original entry on oeis.org

1, 8, 71, 248, 3043, 43024, 89051, 764441, 451021514, 25508567769, 411827311870583771, 525058386770138717020639964821, 528134692562568161116953143877712480332943632586669596859, 2267693117789905604207315326366543773113615946806750184592188584359364943382168221068055512231683584106110223751
Offset: 1

Views

Author

N. J. A. Sloane, Sep 14 2024

Keywords

Examples

			The initial values of S(n) are 1/3, 8/15, 71/105, 248/315, 3043/3465, 43024/45045, 89051/90090, ...
		

Crossrefs

A376054 Denominator of sum S(n) defined in A376052.

Original entry on oeis.org

3, 15, 105, 315, 3465, 45045, 90090, 765765, 451035585, 25508568085, 411827311870584610, 525058386770138717020639964850, 528134692562568161116953143877712480332943632586669596900
Offset: 1

Views

Author

N. J. A. Sloane, Sep 14 2024

Keywords

Examples

			The initial values of S(n) are 1/3, 8/15, 71/105, 248/315, 3043/3465, 43024/45045, 89051/90090, ...
		

Crossrefs

A376059 a(n) is the denominator of the sum S(n) defined in A376058.

Original entry on oeis.org

1, 2, 6, 78, 18330, 1679962830, 22578200883132834030, 6627077016548303724729207245056971365730, 922281145448518091883798423085535218757314338662318933097843039655721026758456630
Offset: 0

Views

Author

N. J. A. Sloane, Sep 14 2024

Keywords

Examples

			The first few values of S(n) are 0, 1/2, 5/6, 77/78, 18329/18330, 1679962829/1679962830, 22578200883132834029/22578200883132834030, ...
		

Crossrefs

Programs

  • Mathematica
    RecurrenceTable[{a[n+1] == Fibonacci[n+1]*a[n]^2 + a[n], a[0] == 1}, a, {n, 0, 8}] (* Amiram Eldar, Sep 15 2024 *)

Formula

a(n+1) = Fibonacci(n+1)*a(n)^2 + a(n), with a(0) = 1.

A376184 Lexicographically earliest sequence of positive integers a(1), a(2), a(3), ... such that for any n > 0, S(n) = Sum_{k = 1..n} b(k)/a(k) < 1, where {b(k)} is the sequence b(1)=5/4, b(2*i)=3/2, b(2*i+1)=6/5 (i>0).

Original entry on oeis.org

2, 5, 17, 341, 92753, 10753782821, 92515075960384748177, 10698799099944699918936107506299150093941, 91571441744782016867976366392607084634231243149599342901251284090792487979854033
Offset: 1

Views

Author

N. J. A. Sloane, Sep 15 2024

Keywords

Comments

This sequence and A376062 were discovered by Rémy Sigrist on Sep 09 2024. The two sequences {b(1)=7/6, b(k)=5/4 for k>1} and {b(1)=5/4, b(2*k)=3/2, b(2*k+1)=6/5 for k>0} are the first sequences {b(i)} discovered with the property that the sums S(n) do not converge to numbers of the form (e_n - 1)/e_n as n-> oo.

Examples

			The initial values of S(n) are 5/8, 37/40, 677/680, 231877/231880, 21507565637/21507565640, 231287689900961870437/231287689900961870440, ...
		

Crossrefs

A376185 a(n) = denominator of the sum S(n) defined in A376062.

Original entry on oeis.org

12, 48, 624, 97968, 2399530224, 1439436326371902768, 517994234419759747473589427583418224, 67079506723028253472357256785558488997471406450171845011442457607246768
Offset: 1

Views

Author

N. J. A. Sloane, Sep 15 2024

Keywords

Examples

			The initial values of S(n) are 7/12, 43/48, 619/624, 97963/97968, 2399530219/2399530224, 1439436326371902763/1439436326371902768 ...
		

Crossrefs

Formula

1/a(n) = 1/a(n-1) - 1/(4*A376062(n)) for n >= 2.

A376186 a(n) = denominator of the sum S(n) defined in A376184.

Original entry on oeis.org

8, 40, 680, 231880, 21507565640, 231287689900961870440, 21397598199889399837872215012598300187880, 228928604361955042169940915981517711585578107873998357253128210226981219949635080
Offset: 1

Views

Author

N. J. A. Sloane, Sep 15 2024

Keywords

Examples

			The initial values of S(n) are 5/8, 37/40, 677/680, 231877/231880, 21507565637/21507565640, 231287689900961870437/231287689900961870440, ...
		

Crossrefs

A375528 a(n) = denominator of Sum_{k = 1..n} 1 / (A000959(k)*A375527(k)).

Original entry on oeis.org

1, 2, 6, 42, 630, 57330, 219172590, 2287458514758690, 523246645674205487113407810300, 34223381526163442974989472671319545640510650941743506071550, 65068880171408068403202506207461768112305307530373013598603234255112994800902512713302330140957468591804616490482800
Offset: 1

Views

Author

N. J. A. Sloane, Sep 01 2024

Keywords

Comments

The first few sums S(n) = Sum_{k = 1..n} 1/(A000959(k)*A375527(k)) are: 1/2, 5/6, 41/42, 629/630, 57329/57330,
219172589/219172590, 2287458514758689/2287458514758690,
523246645674205487113407810299/523246645674205487113407810300, ..., and the first 10 or 11 of these sums have the form (c-1)/c, where c is an integer. The present sequence gives the denominators.
For the harmonic series analog, A374663, Rémy Sigrist has shown that all the partial sums have that form (see A374983), and for the prime number analog, A375581, it seems that all partial sums except for n = 4 and 6 have this property (see A375521/A375522).

Crossrefs

A376060 Lexicographically earliest sequence of positive integers a(0), a(1), a(2), a(3), ... such that for any n > 0, S(n) = Sum_{k = 0..n-1} Catalan(k)/a(k) < 1.

Original entry on oeis.org

2, 3, 13, 391, 426973, 546916547269, 940084230410591812263433, 2872214670866692695441731060944339347071024216683
Offset: 0

Views

Author

N. J. A. Sloane, Sep 14 2024

Keywords

Crossrefs

Formula

a(n+1) = Catalan(n+1)*A376061(n) + 1.
Previous Showing 11-18 of 18 results.