OFFSET
1,1
LINKS
Reiner Moewald, Table of n, a(n) for n = 1..24527
EXAMPLE
332^2 = 110224, i.e., both the integer and its square start with two equal digits.
Also 334^2 = 111556, so 334 is a term.
PROG
(Python)
def zahl(z):
a = str(z)
r = 0
while r < len(a) and a[0] == a[r]:
r = r + 1
b = str(z*z)
s = 0
while r < len(b) and b[0] == b[s]:
s = s + 1
if r >= 2:
return(s-r)
else:
return(-1)
anz = 0
for i in range(1000000):
if zahl(i) >= 0:
anz = anz +1
print(anz, i)
(PARI) nbi(d) = my(nb=1); for(k=2, #d, if (d[k] == d[1], nb++, break)); nb;
isok(n) = my(nb = nbi(digits(n))); (nb > 1) && (nbi(digits(n^2)) >= nb); \\ Michel Marcus, Apr 24 2019
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Reiner Moewald, Jan 20 2019
STATUS
approved