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.

Showing 1-4 of 4 results.

A076483 a(n) = n!*Sum_{k=1..n} (k-1)^k/k!.

Original entry on oeis.org

0, 0, 1, 11, 125, 1649, 25519, 458569, 9433353, 219117905, 5677963451, 162457597961, 5087919552253, 173136159558361, 6361282619516343, 250987334850557369, 10584205713321808529, 475079402305823570849, 22614513693572549266291, 1137911105533216112417161
Offset: 0

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Author

Henry Bottomley, Oct 14 2002

Keywords

Comments

Perhaps the largest possible number of ways of choosing (v1, v2, ..., vn), possibly with repetition, from {b1, b2, ..., bn} with b1 < b2 < ... < bn, such that v1 + v2 + ... + vn < b1 + b2 + ... + bn. Clearly the actual number of ways depends on the particular values of {b1, b2, ..., bn}, but {1, n, n^2, ..., n^(n-1)} produces this result for the number of sums strictly less than (n^n-1)/(n-1) = A023037(n).

Examples

			a(4) = 4!*(0^1/1! + 1^2/2! + 2^3/3! + 3^4/4!) = 0 + 12 + 32 + 81 = 125.
		

Crossrefs

Row sums of A076482.

Programs

  • Mathematica
    Table[n! Sum[(k-1)^k/k!, {k,n}], {n,0,17}] (* Stefano Spezia, Sep 11 2022 *)
  • PARI
    a(n) = n!*sum(k=1, n, (k-1)^k/k!); \\ Seiichi Manyama, Jul 15 2023

Formula

Limit_{n->oo} a(n)/(e*a(n-1)) - n = -1/2.
Limit_{n->oo} a(n)/n^n = 1/(e-1).

A075478 Number of iteration that first becomes smaller than the initial value if Collatz-function (A006370) is iterated, starting with numbers of form 64n+27. Corresponds to selection of every 16th term from A074474.

Original entry on oeis.org

97, 74, 66, 14, 40, 17, 25, 14, 22, 27, 40, 14, 45, 27, 17, 14, 40, 38, 27, 14, 56, 17, 20, 14, 22, 27, 30, 14, 100, 30, 17, 14, 22, 33, 20, 14, 22, 17, 30, 14, 20, 30, 53, 14, 38, 20, 17, 14, 51, 25, 66, 14, 35, 17, 22, 14, 25, 20, 64, 14, 38, 40, 17, 14, 45, 25, 22, 14, 27
Offset: 0

Views

Author

Labos Elemer, Sep 23 2002

Keywords

Comments

Remark that initial values of form 64m+r, if r={3,11,19,27,35,43,51,55} provide first-sink-lengths {7,9,7,9,7,9,7,9} respectively; e.g. {64k+19,192k+58,96k+29,288k+88,144k+44,72k+22,36k+11} submerge first below initial value at the 7th term,36k+11<64k+19.

Examples

			n=0: 64n+27=27, list={27, 82, 41, 46.23.70, ..}, i.e. the 97th term is the first that <27, the initial value.
		

Crossrefs

Formula

a(n)=A075473[64n+27], n=0, ..., 256

A075479 Number of iteration that first becomes smaller than the initial value if Collatz-function (A006370) is iterated, starting with numbers of form 64n+31. Corresponds to selection of every 16th term from A074474.

Original entry on oeis.org

92, 14, 35, 51, 17, 14, 25, 27, 22, 14, 64, 17, 22, 14, 61, 43, 131, 14, 27, 22, 17, 14, 33, 35, 22, 14, 53, 17, 20, 14, 43, 22, 22, 14, 45, 22, 17, 14, 35, 43, 20, 14, 25, 17, 25, 14, 20, 22, 27, 14, 38, 20, 17, 14, 27, 22, 30, 14, 25, 17, 33, 14, 40, 20, 69, 14, 115, 27, 17
Offset: 0

Views

Author

Labos Elemer, Sep 23 2002

Keywords

Comments

Remark that initial values of form 64m+r, if r={3,11,19,27,35,43,51,55} provide first-sink-lengths {7,9,7,9,7,9,7,9} respectively; e.g. {64k+19,192k+58,96k+29,288k+88,144k+44,72k+22,36k+11} submerge first below initial value at the 7th term,36k+11<64k+19.

Examples

			n=1: 64n+31=95,list={95,286,143,430,215,646,323,970, 485,1456,728,364,182,91,274,...}, i.e. the 14th term=91 is the first that <95, the initial value, so a(1)=14.
		

Crossrefs

Formula

a(n)=A075473[64n+31], n=0, ..., 256

A075481 Number of iteration that first becomes smaller than the initial value if Collatz-function (A006370) is iterated, starting with numbers of form 64n+47. Corresponds to selection of every 16th term from A074474.

Original entry on oeis.org

89, 51, 14, 33, 22, 17, 14, 45, 27, 22, 14, 35, 17, 20, 14, 35, 22, 22, 14, 43, 22, 17, 14, 27, 128, 20, 14, 25, 17, 25, 14, 20, 22, 30, 14, 82, 20, 17, 14, 45, 22, 27, 14, 25, 17, 27, 14, 48, 20, 30, 14, 43, 30, 17, 14, 58, 61, 27, 14, 53, 17, 56, 14, 22, 30, 58, 14, 27, 53
Offset: 0

Views

Author

Labos Elemer, Sep 23 2002

Keywords

Comments

Remark that initial values of form 64m+r, if r={3,11,19,27,35,43,51,55} provide first-sink-lengths {7,9,7,9,7,9,7,9} respectively; e.g. {64k+19,192k+58,96k+29,288k+88,144k+44,72k+22,36k+11} submerge first below initial value at the 7th term,36k+11<64k+19.

Examples

			n=2: 64n+47=175,list={175,526,263,790,395,1186,593,1780, 890,445,1336,668,334,167,502,251....}, i.e. the 14th term=167 is the first that <175, the initial value, so a(2)=14.
		

Crossrefs

Formula

a(n)=A075473[64n+47], n=0, ..., 256
Showing 1-4 of 4 results.