login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A032790 Palindromic quotients (k*(k+1)*(k+2)) / (k+(k+1)+(k+2)). 3

%I #15 Jan 25 2022 08:30:22

%S 0,1,5,8,33,161,616,3333,8008,18881,54945,333333,33333333,120232021,

%T 124060421,161656161,185464581,541202145,677191776,3333333333,

%U 6316116136,333333333333,544721127445,616947749616,3333169613333,3333802083333,5412843482145,6352230322536

%N Palindromic quotients (k*(k+1)*(k+2)) / (k+(k+1)+(k+2)).

%C For all i >= 1, 3^{2*i} is a term arising from k = 9^i, where ^ is repeated concatenation. - _Michael S. Branicky_, Jan 24 2022

%H Michael S. Branicky, <a href="/A032790/b032790.txt">Table of n, a(n) for n = 1..48</a>

%t Select[Table[Times@@Range[n,n+2]/(3n+3),{n,0,317*10^4}],PalindromeQ] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, May 06 2019 *)

%o (Python)

%o from itertools import count, islice

%o def ispal(n): s = str(n); return s == s[::-1]

%o def agen():

%o for k in count(0):

%o q, r = divmod(k*(k+2), 3)

%o if r == 0 and ispal(q):

%o yield k, q

%o print([q for k, q in islice(agen(), 31)]) # _Michael S. Branicky_, Jan 24 2022

%Y Cf. A032789.

%K nonn,base

%O 1,3

%A _Patrick De Geest_, May 15 1998

%E a(26) and beyond from _Michael S. Branicky_, Jan 24 2022

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 19 16:38 EDT 2024. Contains 371794 sequences. (Running on oeis4.)