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 1-3 of 3 results.

A347685 First differences of A345882.

Original entry on oeis.org

1, 3, 6, 19, 34, 114, 204, 376, 609, 2253, 3573, 12514, 21160, 34839, 54311, 209489, 327884, 1157266, 1900261, 3060772, 4760209, 18553192, 28734204, 46515286, 70750097, 106748769, 155242841
Offset: 1

Views

Author

N. J. A. Sloane, Sep 18 2021

Keywords

Crossrefs

Cf. A345882.

Extensions

a(25)-a(27) from Chai Wah Wu, Sep 19 2021

A347686 n! - A345882(n).

Original entry on oeis.org

0, 0, 1, 13, 90, 656, 4862, 39938, 362122, 3627433, 39913180, 478994407, 6227001093, 87178250333, 1307674292294, 20922789757983, 355687427756494, 6402373705060610, 121645100407007344, 2432902008172915083, 51090942171702654311, 1124000727777596134102, 25852016738884946540910, 620448401733239380526706, 15511210043330985878651420
Offset: 1

Views

Author

N. J. A. Sloane, Sep 18 2021

Keywords

Crossrefs

Cf. A345882.

A110713 a(n) is the number of distinct products b_1*b_2*...*b_n where 1 <= b_i <= n.

Original entry on oeis.org

1, 3, 10, 25, 91, 196, 750, 1485, 3025, 5566, 23387, 38402, 163268, 284376, 500004, 795549, 3575781, 5657839, 25413850, 40027130, 66010230, 105164280, 490429875, 713491350, 1232253906
Offset: 1

Views

Author

Jonas Wallgren, Sep 15 2005

Keywords

Comments

If * is changed to + the result is A002061. - Michel Marcus and David Galvin, Sep 19 2021

Examples

			a(2) = A027424(2) = 3.
a(3) = A027425(3) = 10.
a(4) = A100437(4) = 25.
		

Crossrefs

Main diagonal of A322967.

Programs

  • PARI
    a(n) = my(l = List()); forvec(x = vector(n, i, [1,n]), listput(l, prod(i = 1, n, x[i])), 1); listsort(l, 1); #l \\ David A. Corneth, Jan 02 2019
    
  • Python
    from math import prod
    from itertools import combinations_with_replacement
    def A110713(n): return len({prod(d) for d in combinations_with_replacement(list(range(1,n+1)),n)}) # Chai Wah Wu, Sep 19 2021

Extensions

a(10)-a(15) from Donovan Johnson, Dec 08 2009
a(16)-a(25) from Gerhard Kirchner, Dec 07 2015
Showing 1-3 of 3 results.