A171703 The first n-fold intrinsically 4-palindromic number (represented in base ten).

9, 624, 19040, 30222192, 592704000, 12040481088, 128024064000, 1024192512000, 3456649728000

Offset: 1

Author

James G. Merickel, Dec 16 2009

Keywords

• nonn
• base

Comments

The fifth and sixth terms are both cubes, exploiting the simple binomial expansion as (m)(m)^3=(m^3)(3m^3)(3m^3)(m^3) for much of their status. - James G. Merickel, Dec 19 2009

The first base in which the fifth term is 4-palindromic is 209. - James G. Merickel, Dec 18 2009

a(10) <= 27653197824000, a(11) <= 27653197824000, a(12) <= 575100098496000, a(13) <= 1733189185728000, a(14) <= 1733189185728000, a(15) <= 8400090327552000. - Hiroaki Yamanouchi, Sep 24 2014

Examples

			a(2)=624 is 4444 in base 5 and 1551 in base 7.
		

Crossrefs

Cf. A171701, A171702, A171704, A171705, A171706, A171740, A171741, A171742.

Extensions

a(5)-a(6) from James G. Merickel, Dec 19 2009

a(7)-a(9) from Hiroaki Yamanouchi, Sep 24 2014