A249834 a(n+1) is the next smallest nontrivial cube beginning with a(n), initial term is 7.

7, 729, 7290099019, 72900990191475181426079596544

Offset: 1

Author

Derek Orr, Dec 03 2014

Keywords

• nonn
• base

Comments

a(5) is an 87-digit number. - Jon E. Schoenfield, Dec 04 2014

Links

• Jon E. Schoenfield, Table of n, a(n) for n = 1..7

Crossrefs

Cf. A048559, A048561, A249799, A249897.

Programs

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++)
a(7)

Python

def f(x):
  n = x
  s = 1
  while s < 10**7:
    if s % 10:
      S = str(s**3)
      if S.startswith(str(n)):
        print(s**3, end=', ')
        n = s**3
    s += 1
f(7)

Extensions

a(4) from Jon E. Schoenfield, Dec 04 2014