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A048411
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Squares whose consecutive digits differ by 1.
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3
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0, 1, 4, 9, 121, 676, 12321, 1234321, 123454321, 12345654321, 1234567654321, 123456787654321, 12345678987654321
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,3
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COMMENTS
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Is it true that all terms are palindromes? - Chai Wah Wu, Apr 06 2018
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LINKS
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FORMULA
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MATHEMATICA
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Select[Range[0, 10^7]^2, Or[# == 0, IntegerLength@ # == 1, Union@ Abs@ Differences@ IntegerDigits@ # == {1}] &] (* Michael De Vlieger, Nov 25 2016 *)
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PROG
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(Haskell)
a048411 n = a048411_list !! (n-1)
a048411_list = filter ((== 1) . a010052) a033075_list
(Python)
from sympy.ntheory.primetest import is_square
def gen(d, s=None):
if d == 0: yield tuple(); return
if s == None:
yield from [(i, ) + g for i in range(1, 10) for g in gen(d-1, s=i)]
else:
if s > 0: yield from [(s-1, ) + g for g in gen(d-1, s=s-1)]
if s < 9: yield from [(s+1, ) + g for g in gen(d-1, s=s+1)]
def afind(maxdigits):
print(0, end=", ")
for d in range(1, maxdigits+1):
for g in gen(d, s=None):
t = int("".join(map(str, g)))
if is_square(t): print(t, end=", ")
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CROSSREFS
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KEYWORD
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nonn,base,more
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AUTHOR
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STATUS
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approved
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