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A323612 Numbers k such that k^2 starts with at least the same number >= 2 of equal digits as does k itself. 1
88, 332, 334, 335, 336, 337, 338, 339, 664, 665, 667, 668, 669, 880, 881, 882, 883, 995, 996, 997, 998, 3317, 3318, 3319, 3320, 3321, 3322, 3323, 3324, 3325, 3326, 3327, 3328, 3329, 3332, 3334, 3335, 3336, 3337, 3338, 3339, 3340, 3341, 3342, 3343, 3344, 3345, 3346, 3347 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
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
Sequence in context: A001347 A003782 A235026 * A235019 A241846 A064022
KEYWORD
nonn,base
AUTHOR
Reiner Moewald, Jan 20 2019
STATUS
approved

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Last modified April 18 21:51 EDT 2024. Contains 371781 sequences. (Running on oeis4.)