A068883 - OEIS

%I #10 Mar 24 2024 15:32:13

%S 1,10,105,1830,10585,107416,1038961,10109256,101410161,1014503490,

%T 10143650961,101072103210,1012143638925,10101274165450,

%U 101014143472945,1010363290981278,10101078125834905,101012169252147076,1010125816103490141

%N Smallest n-digit triangular numbers with property that digits alternate in parity, or 0 if no such number exists.

%H Sean A. Irvine, <a href="/A068883/b068883.txt">Table of n, a(n) for n = 1..50</a>

%e a(4) = 1830 is a term as 1, 8, 3 and 0 have odd and even parity alternately.

%Y Cf. A068876, A030152, A068882, A068884.

%K base,nonn

%O 1,2

%A _Amarnath Murthy_, Mar 19 2002

%E a(7)-a(18) from _Donovan Johnson_, Mar 14 2010

%E a(19) from _Donovan Johnson_, Mar 11 2011