A106372 Smallest number m containing no zeros in base n representation but at least one zero in all base b representations with 1<b<n.

1, 2, 6, 12, 20, 60, 147, 384, 896, 360, 1540, 2760, 2304, 11016, 13860, 6720, 123060, 255024, 658370, 1422720, 1425606, 1179360, 2920500, 12252240, 9989280, 24227280, 242573760, 68424048, 990208128, 410810400, 602751600

Offset

2,2

Comments

A106370(a(n)) = n and A106370(m) <> n for m < a(n).

a(46) = 854710136280. a(45) and all further terms are at least 10^13.

Links

Michael Gottlieb, Table of n, a(n) for n = 2..44 (terms 2..32 from Reinhard Zumkeller, terms 33..44 from Michael Gottlieb).

Michael Gottlieb, C++ program to compute values.

Example

a(10)=896, A106370(896)=10: 896[base-9]='1205',
896[octal]='1600', 896[base-7]='2420', 896[base-6]='4052',
896[base-5]='12041', 896[base-4]='32000', 896[ternary]='1020012',
896[binary]='1110000000'.

Prog

(Haskell)
import Data.List (elemIndex); import Data.Maybe (fromJust)
a106372 = (+ 1) . fromJust . (`elemIndex` a106370_list)
-- Reinhard Zumkeller, Apr 12 2015

Crossrefs

Cf. A106370, A119354.

Sequence in context: A290209 A286780 A099885 * A354895 A214916 A323291

Adjacent sequences: A106369 A106370 A106371 * A106373 A106374 A106375

Keyword

nonn,base

Author

Reinhard Zumkeller, May 01 2005

Extensions

Generated a(33)-a(44) and a(46), with linked C++ program

Status

approved