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.

User: Fabian Rothelius

Fabian Rothelius's wiki page.

Fabian Rothelius has authored 19 sequences. Here are the ten most recent ones:

A059920 If m/n = q + r/n (r < n, n,m >=1), then array a(m,n) = qr (meaning q followed by r). Read by antidiagonals.

Original entry on oeis.org

10, 1, 20, 1, 10, 30, 1, 2, 11, 40, 1, 2, 10, 20, 50, 1, 2, 3, 11, 21, 60, 1, 2, 3, 10, 12, 30, 70, 1, 2, 3, 4, 11, 20, 31, 80, 1, 2, 3, 4, 10, 12, 21, 40, 90, 1, 2, 3, 4, 5, 11, 13, 22, 41, 100, 1, 2, 3, 4, 5, 10, 12, 20, 30, 50, 110, 1, 2, 3, 4, 5, 6, 11, 13, 21, 31, 51, 120, 1, 2, 3
Offset: 1

Author

Fabian Rothelius, Feb 09 2001

Keywords

Examples

			a(7,3)=21 because 7/3=2+1/3; a(273,24)=119 because 273/24=11+9/24.
Array begins
10 20 30 40 50...
1 10 11 20 21 ...
1 2 10 11 ...
		

A059922 Each term in the table is the product of the two terms above it + 1.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 10, 4, 1, 1, 5, 41, 41, 5, 1, 1, 6, 206, 1682, 206, 6, 1, 1, 7, 1237, 346493, 346493, 1237, 7, 1, 1, 8, 8660, 428611842, 120057399050, 428611842, 8660, 8, 1, 1, 9, 69281, 3711778551721, 51458022952549550101, 51458022952549550101, 3711778551721, 69281, 9, 1
Offset: 0

Author

Fabian Rothelius, Feb 09 2001

Keywords

Comments

Row sums are A059731.

Examples

			Triangle begins:
1;
1,1;
1,2,1;
1,3,3,1;
1,4,10,4,1; ...
		

Crossrefs

Programs

  • Haskell
    a059922 n k = a059922_tabl !! n !! k
    a059922_flattened = concat a059922_tabl
    a059922_tabl = iterate (\rs ->
       zipWith (+) (0 : reverse (0 : replicate (length rs - 1) 1))
                   $ zipWith (*) ([1] ++ rs) (rs ++ [1])) [1]
    a059730 n = a059922_tabl !! n !! (n-3)
    a059731 n = sum (a059922_tabl !! n)
    a059732 n = a059922_tabl !! (2*n) !! n
    a059733 n = a059922_tabl !! n !! n `div` 2
    -- Reinhard Zumkeller, Jun 22 2011
  • Maple
    aaa := proc(m,n) option remember; if n>m or n<0 then 0; elif m=0 and n=0 then 1; else aaa(m-1,n-1)*aaa(m-1,n)+1; fi; end;
  • Mathematica
    a[0, 0] = 1; a[m_, n_] /; (n > m || n < 0) = 0; a[m_, n_] := a[m, n] = a[m-1, n-1]*a[m-1, n] + 1; Table[a[m, n], {m, 0, 9}, {n, 0, m}] // Flatten (* Jean-François Alcover, Sep 10 2013 *)

Formula

a(m, n) = a(m-1, n-1)*a(m-1, n)+1, a(0, 0) = 1, a(m, n) = 0 iff n>m or n<0.

Extensions

More terms from N. J. A. Sloane and Larry Reeves, Feb 09 2001.
Corrected by Jonathan Wellons (wellons(AT)gmail.com), May 24 2008

A059674 Square array a(m,n) = binomial(max(m,n), min(m,n)) (m>=0, n>=0) read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 3, 1, 3, 1, 1, 4, 3, 3, 4, 1, 1, 5, 6, 1, 6, 5, 1, 1, 6, 10, 4, 4, 10, 6, 1, 1, 7, 15, 10, 1, 10, 15, 7, 1, 1, 8, 21, 20, 5, 5, 20, 21, 8, 1, 1, 9, 28, 35, 15, 1, 15, 35, 28, 9, 1, 1, 10, 36, 56, 35, 6, 6, 35, 56, 36, 10, 1, 1, 11, 45, 84, 70, 21, 1, 21, 70, 84
Offset: 0

Author

Fabian Rothelius, Feb 05 2001

Keywords

Examples

			a(2,4) = binomial(max(2,4), min(2,4)) = binomial(4,2) = 6.
Square begins:
1 1 1 1 1 1 ...
1 1 2 3 4 5 ...
1 2 1 3 6 10...
1 3 3 1 4 10 ...
		

Crossrefs

Cf. A007318.

Programs

  • Mathematica
    a[m_, n_] := If[m >= n, Binomial[m, n], Binomial[n, m]]; Table[a[m-n, n], {m, 0, 12}, {n, 0, m}] // Flatten (* Jean-François Alcover, Oct 10 2012 *)

Formula

Square array equals A007318 + transpose(A007318) - I, where I denotes the infinite identity matrix. - Peter Bala, Aug 11 2015

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Feb 06 2001

A059232 a(1)= 1, a(n) = (a(n-1)^a(n-1)) + n.

Original entry on oeis.org

1, 3, 30, 205891132094649000000000000000000000000000004
Offset: 1

Author

Fabian Rothelius, Jan 20 2001

Keywords

Comments

The next term is too large to include.

Examples

			a(2) = 1^1 + 2 = 3.
a(3) = 3^3 + 3 = 27 + 3 = 30.
		

Programs

  • Mathematica
    RecurrenceTable[{a[1]==1,a[n]==a[n-1]^a[n-1]+n},a,{n,4}] (* Harvey P. Dale, Dec 27 2012 *)
  • PARI
    { for (n = 1, 4, a=if (n==1, 1, a^a + n); write("b059232.txt", n, " ", a); ) } \\ Harry J. Smith, Jun 25 2009

A059573 Polyotessamino numbers T(n,k) (1<=k<=n): take all the polyominoes with n cells (including those with holes but excluding rotations and reflections); fill them as completely as possible with rectangular 1 X k tiles; T(n,k) is number of ways of doing this.

Original entry on oeis.org

1, 1, 1, 2, 4, 1, 5, 8, 4, 1, 12, 34, 18, 4, 1, 35, 85, 61, 22, 5, 1
Offset: 1

Author

Fabian Rothelius, Jan 22 2001

Keywords

Comments

Warning: This appears to be an erroneous version of A308437. - R. J. Mathar, May 27 2019

Examples

			1;
1,1;
2,4,1;
5,8,4,1;
12,34,18,4,1;
35,85,61,22,5,1; ...
		

Crossrefs

Cf. A000105.

Formula

T(n,1) = A000105(n).

A059527 Decimal expansion of imaginary part of solution to z = log z.

Original entry on oeis.org

1, 3, 3, 7, 2, 3, 5, 7, 0, 1, 4, 3, 0, 6, 8, 9, 4, 0, 8, 9, 0, 1, 1, 6, 2, 1, 4, 3, 1, 9, 3, 7, 1, 0, 6, 1, 2, 5, 3, 9, 5, 0, 2, 1, 3, 8, 4, 6, 0, 5, 1, 2, 4, 1, 8, 8, 7, 6, 3, 1, 2, 7, 8, 1, 9, 1, 4, 3, 5, 0, 5, 3, 1, 3, 6, 1, 2, 0, 4, 9, 8, 8, 4, 1, 8, 8, 8, 1, 3, 2, 3, 4, 3, 8, 7, 9, 4, 0, 1, 5, 6, 1, 0, 3, 8
Offset: 1

Author

Fabian Rothelius, Jan 21 2001

Keywords

Comments

Repeatedly take logs, starting from any number not equal to 0, 1, e, e^e, e^(e^e), etc. and you will converge to 0.31813150... + 1.33723570...*I.

Examples

			z = 0.31813150520476413531265425158766451720351761387139986692237... + 1.33723570143068940890116214319371061253950213846051241887631... *i.
		

Crossrefs

Real part is A059526.
Cf. A030178.

Programs

  • Mathematica
    RealDigits[ Im[ N[ FixedPoint[ Log, 1 + I, 910], 105]]] [[1]]
    RealDigits[ N[ Im[ ProductLog[-1]], 105]][[1]] (* Jean-François Alcover, Feb 01 2012 *)
  • PARI
    z=I;for(k=1,16000,z=log(z));imag(z)  \\ Using realprecision \p 2010. - Stanislav Sykora, Jun 07 2015
    
  • PARI
    z=I; for(k=1, 10, z-=(z-log(z))/(1-1/z)); imag(z) \\ Jeremy Tan, Sep 23 2017

Extensions

More terms from Vladeta Jovovic, Feb 26 2001
Edited and extended by Robert G. Wilson v, Aug 22 2002

A059526 Decimal expansion of real part of solution to z = log z.

Original entry on oeis.org

3, 1, 8, 1, 3, 1, 5, 0, 5, 2, 0, 4, 7, 6, 4, 1, 3, 5, 3, 1, 2, 6, 5, 4, 2, 5, 1, 5, 8, 7, 6, 6, 4, 5, 1, 7, 2, 0, 3, 5, 1, 7, 6, 1, 3, 8, 7, 1, 3, 9, 9, 8, 6, 6, 9, 2, 2, 3, 7, 8, 6, 0, 6, 2, 2, 9, 4, 1, 3, 8, 7, 1, 5, 5, 7, 6, 2, 6, 9, 7, 9, 2, 3, 2, 4, 8, 6, 3, 8, 4, 8, 9, 8, 6, 3, 6, 1, 6, 3, 8, 4, 4, 2, 1, 4
Offset: 0

Author

Fabian Rothelius, Jan 21 2001

Keywords

Comments

Repeatedly take logs, starting from any number not equal to 0, 1, e, e^e, e^(e^e), etc. and you will converge to 0.31813150... + 1.33723570...*I.
A complex number w with a negative imaginary part will converge to the conjugate of z since log(conjugate(w)) = conjugate(log(w)). - Gerald McGarvey, Mar 02 2009
This z and its conjugate are the only two complex solutions of z=log(z) on the principal branch of log(z), and of exp(z)=z for |arg(z)| <= Pi. They are also the only nontrivial (z!=0) principal branch solutions of z=W(z^2), W being the Lambert W-function. Though the two values are iterative attractors of the mapping z->log(z), the convergence is rather slow; the precision improves by slightly more than one binary bit every 2.25 iterations (about 7500 iterations are needed to make stable the first 1000 decimal digits). - Stanislav Sykora, Jun 07 2015

Examples

			z = 0.31813150520476413531265425158766451720351761387139986692237... + 1.33723570143068940890116214319371061253950213846051241887631... *i
		

Crossrefs

Imaginary part is A059527.
Cf. A030178.
Cf: A277681 (another fixed point of exp(z)).

Programs

  • Mathematica
    RealDigits[ Re[ N[ FixedPoint[ Log, 1 + I, 910], 105]]] [[1]]
    RealDigits[ N[ Re[ ProductLog[-1]], 105]][[1]] (* Jean-François Alcover, Feb 01 2012 *)
    RealDigits[Re[x/.FindRoot[x-Log[x]==0,{x,.5,1},WorkingPrecision->200]],10,120][[1]] (* Harvey P. Dale, Aug 07 2022 *)
  • PARI
    z=I;for(k=1,16000,z=log(z));real(z) \\ Stanislav Sykora, Jun 07 2015 \\ Using realprecision \p 2010
    
  • PARI
    z=I; for(k=1, 10, z-=(z-log(z))/(1-1/z)); real(z) \\ Jeremy Tan, Sep 23 2017

Extensions

More terms from Vladeta Jovovic, Feb 26 2001
Edited and extended by Robert G. Wilson v, Aug 22 2002

A059124 Number of letters in n (in Swedish).

Original entry on oeis.org

4, 3, 3, 3, 4, 3, 3, 3, 4, 3, 3, 4, 4, 7, 7, 6, 6, 7, 5, 6, 5, 8, 8, 8, 9, 8, 8, 8, 9, 8, 7, 10, 10, 10, 11, 10, 10, 10, 11, 10, 6, 9, 9, 9, 10, 9, 9, 9, 10, 9, 6, 9, 9, 9, 10, 9, 9, 9, 10, 9, 6, 9, 9, 9, 10, 9, 9, 9, 10, 9, 7, 10, 10, 10, 11, 10, 10, 10, 11, 10, 5, 8, 8, 8, 9, 8, 8, 8, 9, 8, 6
Offset: 0

Author

Fabian Rothelius, Feb 14 2001

Keywords

Examples

			noll, ett, två, tre, fyra, fem, sex, sju, åtta, nio, tio, elva, ...
		

A060473 a(n) = numerator of phi(n)/(n+1), where phi(n) is Euler's phi, A000010.

Original entry on oeis.org

1, 1, 1, 2, 2, 2, 3, 4, 3, 4, 5, 4, 6, 2, 1, 8, 8, 6, 9, 8, 6, 10, 11, 8, 10, 4, 9, 12, 14, 8, 15, 16, 10, 16, 2, 12, 18, 6, 3, 16, 20, 12, 21, 4, 12, 22, 23, 16, 21, 20, 8, 24, 26, 18, 5, 8, 18, 28, 29, 16, 30, 10, 9, 32, 8, 20, 33, 32, 22, 24, 35, 24, 36, 12, 10, 36, 10, 24, 39, 32, 27, 40, 41
Offset: 1

Author

Fabian Rothelius, Mar 16 2001

Keywords

Comments

a(A203966(n)) = 1. - Robert G. Wilson v, Jul 05 2014

Examples

			a(7) = 3 because phi(7)/(7+1) = 6/8 = 3/4.
		

Crossrefs

Programs

  • Maple
    with(numtheory,phi): seq(numer(phi(n)/(n+1)), n=1..50);
  • Mathematica
    Numerator/@Table[EulerPhi[n]/(n+1),{n,90}] (* Harvey P. Dale, May 11 2011 *)
  • PARI
    { for (n=1, 1000, write("b060473.txt", n, " ", numerator(eulerphi(n)/(n + 1))); ) } \\ Harry J. Smith, Jul 05 2009

Extensions

More terms from Asher Auel, Mar 16 2001

A060474 a(n) = denominator of phi(n)/(n+1), where phi(n) is Euler's phi, A000010.

Original entry on oeis.org

2, 3, 2, 5, 3, 7, 4, 9, 5, 11, 6, 13, 7, 5, 2, 17, 9, 19, 10, 21, 11, 23, 12, 25, 13, 9, 14, 29, 15, 31, 16, 33, 17, 35, 3, 37, 19, 13, 5, 41, 21, 43, 22, 9, 23, 47, 24, 49, 25, 51, 13, 53, 27, 55, 7, 19, 29, 59, 30, 61, 31, 21, 16, 65, 11, 67, 34, 69, 35, 71, 36, 73, 37, 25, 19, 77, 13, 79, 40
Offset: 1

Author

Fabian Rothelius, Mar 16 2001

Keywords

Crossrefs

Programs

  • Maple
    with(numtheory,phi): seq(denom(phi(n)/(n+1)), n=1..50);
  • Mathematica
    Denominator[Table[EulerPhi[n]/(n+1),{n,80}]] (* Harvey P. Dale, Apr 13 2012 *)
  • PARI
    { for (n=1, 1000, write("b060474.txt", n, " ", denominator(eulerphi(n)/(n + 1))); ) } \\ Harry J. Smith, Jul 13 2009
    
  • Python
    from sympy import totient, gcd
    def A060474(n): return (n+1)//gcd(n+1,totient(n)) # Chai Wah Wu, Apr 02 2021

Extensions

More terms from Asher Auel, Mar 16 2001
A Maple program that should have been a PARI program removed by Harry J. Smith, Jul 13 2009