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.

A098668 Right edge of triangle A098666.

Original entry on oeis.org

1, 2, 3, 2, 5, 1, 7, 8, 9, 1, 11, 1, 13, 2, 5, 8, 17, 9, 19, 1, 7, 2, 23, 4, 25, 1, 27, 2, 29, 1, 31, 32, 11, 1, 7, 3, 37, 1, 13, 20, 41, 3, 43, 2, 3, 1, 47, 16, 49, 25, 51, 1, 53, 9, 11, 8, 19, 1, 59, 1, 61, 2, 9, 32, 65, 1, 67, 1, 23, 7, 71, 36, 73, 1, 25, 2, 11, 1, 79, 16, 81, 1, 83, 7, 17
Offset: 1

Views

Author

Reinhard Zumkeller, Sep 20 2004

Keywords

Comments

a(n) = A098666(n,n);
a(n) = n iff n=1 or n is prime.

A098667 Max{m: A098666(n,k)=1 for 1<=k<=m<=n}.

Original entry on oeis.org

1, 1, 1, 2, 2, 4, 4, 4, 4, 6, 6, 6, 6, 8, 10, 10, 10, 10, 10, 10, 10, 12, 12, 12, 12, 16, 16, 16, 16, 16, 16, 16, 16, 18, 18, 18, 18, 22, 22, 22, 22, 22, 22, 22, 22, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 30, 30, 30, 30, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 40
Offset: 1

Views

Author

Reinhard Zumkeller, Sep 20 2004

Keywords

Comments

A098666(n,k)=1 for k<=a(n), A098666(n,a(n)+1)>1 for n>1.

A098669 Numbers of rows ending with ones in triangle A098666.

Original entry on oeis.org

1, 6, 10, 12, 20, 26, 30, 34, 38, 46, 52, 58, 60, 66, 68, 74, 78, 82, 86, 92, 102, 105, 106, 114, 116, 122, 130, 134, 136, 142, 146, 148, 156, 164, 165, 166, 172, 178, 186, 190, 194, 202, 206, 212, 218, 222, 226, 228, 230, 238, 244, 246, 252, 262, 264, 273, 274
Offset: 1

Views

Author

Reinhard Zumkeller, Sep 20 2004

Keywords

Comments

A098668(a(n)) = 1;
a(22)=105 is the smallest odd term, 105=3*5*7.

A008339 a(1)=1; for n >= 1, a(n+1) = lcm(a(n),n) / gcd(a(n),n).

Original entry on oeis.org

1, 1, 2, 6, 6, 30, 5, 35, 280, 2520, 252, 2772, 231, 3003, 858, 1430, 5720, 97240, 437580, 8314020, 415701, 969969, 176358, 4056234, 2704156, 67603900, 2600150, 70204050, 10029150, 290845350, 9694845, 300540195, 9617286240, 35263382880, 1037158320
Offset: 1

Views

Author

N. J. A. Sloane

Keywords

Comments

a(n+1) = Product(A098666(n,k): 1<=k<=n), row-products of triangle A098666. - Reinhard Zumkeller, Sep 20 2004
a(n+1) is divisible by all primes in (n/2, n]; thus lim_{n->infinity} a(n) = infinity. - Franklin T. Adams-Watters, Dec 13 2006

Links

Crossrefs

Cf. A249831.

Programs

  • Maple
    A008339 := proc(n) option remember; if n = 1 then 1 else lcm(A008339(n-1), n-1)/gcd(A008339(n-1), n-1); fi; end;
  • Mathematica
    FoldList[ LCM[ #1, #2 ]/GCD[ #1, #2 ]&, 1, Range[ 30 ] ] (* Olivier Gérard, Aug 15 1997 *)

Formula

a(1) = 1, a(n) = a(n-1)*r/s where y is the largest divisor of a(n-1) with r*s = n. - Amarnath Murthy, Jul 01 2003
a(1) = 1, a(n+1) = a(n)*n/gcd(a(n),n)^2. - Franklin T. Adams-Watters, Dec 13 2006
Showing 1-4 of 4 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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