A247873 For bases b = 2, 3, ..., n, let the base-b expansion of n be [c_{1,b} c_{2,b} .. c_{r_b,b}], with the most significant "digit" on the left, 0 <= c_{i,b} < b, and c_{1,b} != 0; then a(n) is the number whose base-n expansion is c_{1,n} c_{2,n} ... c_{r_n,n} c_{1,n-1} ... c_{1,2} c_{2,2} ... c_{r_2,2}.

2, 31, 4432, 410276, 62490570, 14171701216, 35813773615616, 152181888842647477, 101112131420221011010, 82143288287525988974045, 80099420009719637413225296, 92321614375701368079704516014, 124155371020622584901673311361738, 192664414286229496774895472345022366

Offset

2,1

Comments

The base-n expansion of a(n) is the concatenations of the expansions of n in bases n, n-1, ..., 3, 2, regarding all the coefficients as numbers in the range 0 to n-1.

Links

Hiroaki Yamanouchi, Table of n, a(n) for n = 2..100

Example

For n = 4 we first find 4 in base 4 = 1,0, then 4 in base 3 = 1,1, and 4 in base 2 = 1,0,0. The full string we now have is '1,0,1,1,1,0,0'. This is the base-4 expansion of the number a(4) = 1*4^6 + 0*4^5 + 1*4^4 + 1*4^3 + 1*4^2 + 0*4^1 + 0*4^0 = 4432.

Crossrefs

Cf. A247878, A247880.

Sequence in context: A244441 A004072 A113030 * A281901 A357176 A018802

Adjacent sequences: A247870 A247871 A247872 * A247874 A247875 A247876

Keyword

nonn,base,easy

Author

Talha Ali, Sep 25 2014

Extensions

Definition revised by N. J. A. Sloane, Sep 27 2014

a(7)-a(15) from Hiroaki Yamanouchi, Oct 02 2014

Status

approved