A218559 Sum_{i=0..n-1} i*(n^(i+1)-1)/(n-1)*n^(i(i+1)/2).

0, 6, 714, 1047188, 30515132780, 21936856591278330, 459986443452971306412268, 324518550895166392891543292552264, 8727963565271662417355532872177263437534624, 9999999999888888888777777776666666555555444443333222110

Offset: 1

Author

M. F. Hasler, Nov 02 2012

Keywords

• nonn
• base

Comments

Largest number which can be written in base n using d+1 times the digit d, d=0,...,n-1. (Or: such that for each k=1,...,n, some digit is used exactly k times.)

Examples

			Written in the respective bases, a(2) = 6 = 110[2], a(3) = 714 = 222110[3], a(4) = 1047188 = 33322110[4], etc.
		

Crossrefs

Cf. A218556, A210666, A182040; A167819, A031948.

Programs

PARI

a(b)=sum(i=1,b-1,(b^(i+1)-1)\(b-1)*b^(i*(i+1)\2)*i)