A274943 Smallest self-descriptive number in base b, or -1 if no such number exists.

-1, -1, 100, 1425, -1, 389305, 8946176, 225331713, 6210001000, 186492227801, 6073061476032, 213404945384449, 8054585122464440, 325144322753909625, 13983676842985394176

Offset: 2

Author

N. J. A. Sloane, Jul 23 2016, following an email from Amarnath Krishnamurthy [Amarnath Murthy] and in addition using data from A108551

Keywords

• sign
• base
• more

Comments

A self-descriptive number in base b has b digits, indexed by 0 ... b-1 and for all n, the n-th digit equals the number of n's in the number. In base 10 there is exactly one such number, 6210001000.

Examples

			1210_4 = 100, 21200_5 = 1425, 3211000_7 = 389305,
42101000_8 = 8946176, 521001000_9 = 225331713, 6210001000_10,
72100001000_11 = 186492227801, 821000001000_12 = 6073061476032,
9210000001000_13 = 213404945384449, (10)2100000001000_14 =
8054585122464440, (11)21000000001000_15 = 325144322753909625,
(12)21000000001000_16 = 13983676842985394176, etc.
		

Crossrefs

Very similar to A108551.