A028337 Palindromes of the form n(n+1).

2, 6, 272, 6006, 289982, 2629262, 6039306, 27999972, 28233282, 2704884072, 20278187202, 20591819502, 2592587852952, 2936231326392, 21809166190812, 27237788773272, 229145919541922, 233552101255332, 250087292780052, 2243922442293422, 2570769009670752, 20333113431133302, 27785925652958772

Offset

1,1

Links

Table of n, a(n) for n=1..23.

P. De Geest, Palindromic pronic numbers of the form n(n+1)

Eric Weisstein's World of Mathematics, Palindromic Number.

Eric Weisstein's World of Mathematics, Pronic Number.

Example

272 belongs to the sequence as 272 = 16*17 is a palindrome.

Mathematica

Select[2*Accumulate[Range[15820000]], IntegerDigits[#] == Reverse[ IntegerDigits[#]]&] (* Harvey P. Dale, Sep 03 2013 *)

Prog

(Python)
A028337_list, n = [], 0
for i in range(2, 10**6, 2):
....n += i
....s = str(n)
....if s == s[::-1]:
........A028337_list.append(n) # Chai Wah Wu, Jan 15 2015

Crossrefs

Cf. A028336.

Sequence in context: A232696 A007190 A164829 * A215293 A264410 A135014

Adjacent sequences: A028334 A028335 A028336 * A028338 A028339 A028340

Keyword

nonn,base

Author

Patrick De Geest

Extensions

a(20)-a(23) from G. C. Greubel, Nov 04 2017

Status

approved