A249834 - OEIS

%I #29 Dec 19 2014 19:47:30

%S 7,729,7290099019,72900990191475181426079596544

%N a(n+1) is the next smallest nontrivial cube beginning with a(n), initial term is 7.

%C a(5) is an 87-digit number. - _Jon E. Schoenfield_, Dec 04 2014

%H Jon E. Schoenfield, <a href="/A249834/b249834.txt">Table of n, a(n) for n = 1..7</a>

%o (Python)

%o def f(x):

%o ..n = x

%o ..s = 1

%o ..while s < 10**7:

%o ....if s % 10:

%o ......S = str(s**3)

%o ......if S.startswith(str(n)):

%o ........print(s**3, end=', ')

%o ........n = s**3

%o ....s += 1

%o f(7)

%o (PARI) a(n)=k=n; s=1; while(s<10^7, if(s%10, if(s^3\(10^(#Str(s^3)-#Str(k)))==k, print1(s^3, ", "); k=s^3)); s++)

%o a(7)

%Y Cf. A048559, A048561, A249799, A249897.

%K nonn,base

%O 1,1

%A _Derek Orr_, Dec 03 2014

%E a(4) from _Jon E. Schoenfield_, Dec 04 2014