login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A249155 Palindromic in bases 6 and 15. 7
0, 1, 2, 3, 4, 5, 7, 14, 80, 160, 301, 602, 693, 994, 1295, 1627, 1777, 2365, 2666, 5296, 5776, 6256, 17360, 34720, 51301, 52201, 105092, 155493, 209284, 587846, 735644, 7904800, 11495701, 80005507, 80469907, 83165017, 89731777, 90196177 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Intersection of A029953 and A029960.

LINKS

Ray Chandler and Chai Wah Wu, Table of n, a(n) for n = 1..71 (terms < 6^28). First 65 terms from Ray Chandler.

Attila Bérczes and Volker Ziegler, On Simultaneous Palindromes, arXiv:1403.0787 [math.NT]

EXAMPLE

301 is a term since 301 = 1221 base 6 and 301 = 151 base 15.

MATHEMATICA

palQ[n_Integer, base_Integer] := Block[{idn = IntegerDigits[n, base]}, idn == Reverse[idn]]; Select[Range[10^6] - 1, palQ[#, 6] && palQ[#, 15] &]

PROG

(Python)

def palQ(n, b): # check if n is a palindrome in base b

....s = digits(n, b)

....return s == s[::-1]

def palQgen(l, b): # generator of palindromes in base b of length <= 2*l

....if l > 0:

........yield 0

........for x in range(1, l+1):

............for y in range(b**(x-1), b**x):

................s = digits(y, b)

................yield int(s+s[-2::-1], b)

............for y in range(b**(x-1), b**x):

................s = digits(y, b)

................yield int(s+s[::-1], b)

A249155_list = [n for n in palQgen(8, 6) if palQ(n, 15)] # Chai Wah Wu, Nov 29 2014

CROSSREFS

Cf. A007632, A060792, A249156, A249157, A249158.

Sequence in context: A133476 A131023 A069514 * A101012 A048659 A065774

Adjacent sequences:  A249152 A249153 A249154 * A249156 A249157 A249158

KEYWORD

nonn,base

AUTHOR

Ray Chandler, Oct 27 2014

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 28 21:37 EDT 2020. Contains 334690 sequences. (Running on oeis4.)