Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A051875
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A051875 23-gonal numbers: n(21n-19)/2. +0
1
0, 1, 23, 66, 130, 215, 321, 448, 596, 765, 955, 1166, 1398, 1651, 1925, 2220, 2536, 2873, 3231, 3610, 4010, 4431, 4873, 5336, 5820, 6325, 6851, 7398, 7966, 8555, 9165, 9796, 10448, 11121, 11815, 12530, 13266, 14023, 14801, 15600 (list; graph; listen)
OFFSET

0,3

REFERENCES

A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, p. 189.

FORMULA

a(n)=21*n+a(n-1)-41 (with a(1)=0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 13 2009]

EXAMPLE

For n=2, a(2)=21*2+0-41=1; n=3, a(3)=21*3+1-41=23; n=4, a(4)=21*4+23-41=66 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 13 2009]

MATHEMATICA

s=0; lst={s}; Do[s+=n++ +1; AppendTo[lst, s], {n, 0, 7!, 21}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 16 2008]

CROSSREFS

Sequence in context: A107692 A089823 A001346 this_sequence A125872 A104945 A141849

Adjacent sequences: A051872 A051873 A051874 this_sequence A051876 A051877 A051878

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Dec 15 1999

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified December 20 16:54 EST 2009. Contains 171081 sequences.


AT&T Labs Research