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.

A016189 a(n) = 10^n - 9^n.

Original entry on oeis.org

0, 1, 19, 271, 3439, 40951, 468559, 5217031, 56953279, 612579511, 6513215599, 68618940391, 717570463519, 7458134171671, 77123207545039, 794108867905351, 8146979811148159, 83322818300333431, 849905364703000879, 8649148282327007911, 87842334540943071199, 890581010868487640791
Offset: 0

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Author

Keywords

Comments

Almost all numbers contain any given sequence of digits (in any base) [Theorem 143 of Hardy and Wright]. a(7) = 5217031, more than 52% of the numbers < 10^7 contain any given nonzero decimal digit. - Frank Ellermann, May 30 2001
a(n) gives the number of integers from 0 to 10^n-1 which contain (at least) any one given decimal digit except 0. - Michael Taktikos, Aug 24 2004
These are the numerators of a(n)=(integral{x=0 to 0.2} (1-0.5*x)^n dx). E.g., a(3)=3439/20000. The denominators are b(n)=5*(n+1)*10^n. E.g., b(3)=20000. - Al Hakanson (hawkuu(AT)excite.com), Feb 22 2004
Binomial transforms of sequences defined by a(n)=(C+1)^n-C^n are the sequences (C+2)^n-(C+1)^n. The binomial transform of this here is in A016195, for example. - R. J. Mathar, Nov 27 2008
First differences are given in A088924. - M. F. Hasler, May 04 2015

References

  • G. H. Hardy and E. M. Wright, An Introduction to the Theory of Numbers, 5th ed., Oxford Univ. Press, 1979, th. 143

Crossrefs

Base 2: A000225, 3: A001047, 4: A005061, 5: A005060, 6: A005062, base 7: A016169, 8: A016177, 9: A016185 11: A016195 12: A016197.
Equals A155671 - 1.

Programs

Formula

G.f.: x/((1-9x)(1-10x)).
a(0) = 0, a(1) = 1, then a(n+1) = 9*a(n) + 10^n.
a(n) = 19*a(n-1) - 90*a(n-2), n > 1; a(0)=0, a(1)=1. - Philippe Deléham, Jan 01 2009
E.g.f.: e^(10*x) - e^(9*x). - Mohammad K. Azarian, Jan 14 2009

A155672 11^n-9^n+1^n.

Original entry on oeis.org

1, 3, 41, 603, 8081, 102003, 1240121, 14704203, 171312161, 1970527203, 22450640201, 253930611003, 2855998840241, 31980846315603, 356873041128281, 3971357037321003, 44096709674720321, 488769846799627203
Offset: 0

Views

Author

Mohammad K. Azarian, Feb 01 2009

Keywords

Crossrefs

Programs

  • Mathematica
    Table[11^n-9^n+1,{n,0,30}] (* or *) LinearRecurrence[{21,-119,99},{1,3,41},30] (* Harvey P. Dale, May 07 2019 *)

Formula

G.f.: 1/(1-11*x)-1/(1-9*x)+1/(1-x). E.g.f.: e^(11*x)-e^(9*x)+e^x.
a(n)=20*a(n-1)-99*a(n-2)+80 with a(0)=1, a(1)=3 [From Vincenzo Librandi, Jul 21 2010]

A155673 a(n) = 11^n + 10^n - 1.

Original entry on oeis.org

1, 20, 220, 2330, 24640, 261050, 2771560, 29487170, 314358880, 3357947690, 35937424600, 385311670610, 4138428376720, 44522712143930, 479749833583240, 5177248169415650, 55949729863572160, 605447028499293770
Offset: 0

Views

Author

Mohammad K. Azarian, Feb 01 2009

Keywords

Crossrefs

Programs

  • Mathematica
    Table[11^n+10^n-1,{n,0,20}] (* Harvey P. Dale, Feb 24 2011 *)

Formula

G.f.: 1/(1-11*x)+1/(1-10*x)-1/(1-x).
E.g.f.: e^(11*x)+e^(10*x)-e^x.
a(n) = 21*a(n-1)-110*a(n-2)-90 with a(0)=1, a(1)=20. - Vincenzo Librandi, Jul 21 2010
a(n) = 22*a(n-1)-131*a(n-2)+110*a(n-3). - Wesley Ivan Hurt, May 19 2024

A155674 11^n-10^n+1^n.

Original entry on oeis.org

1, 2, 22, 332, 4642, 61052, 771562, 9487172, 114358882, 1357947692, 15937424602, 185311670612, 2138428376722, 24522712143932, 279749833583242, 3177248169415652, 35949729863572162, 405447028499293772
Offset: 0

Views

Author

Mohammad K. Azarian, Feb 01 2009

Keywords

Crossrefs

Formula

G.f.: 1/(1-11*x)-1/(1-10*x)+1/(1-x). E.g.f.: e^(11*x)-e^(10*x)+e^x.
a(n)=21*a(n-1)-110*a(n-2)+90 with a(0)=1, a(1)=2 [From Vincenzo Librandi, Jul 21 2010]
Showing 1-4 of 4 results.