

A116260


n times n+4 gives the concatenation of two numbers m and m4.


8



9, 99, 999, 9999, 99999, 999999, 9999999, 99999999, 999999999, 9999999999, 36363636362, 45454545453, 54545454544, 63636363635, 72727272726, 81818181817, 90909090908, 99999999999, 999999999999, 9999999999999
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OFFSET

1,1


LINKS



FORMULA



EXAMPLE

99999999 * 100000003 = 100000001//99999997, where // denotes concatenation.


PROG

(Python)
from itertools import count, islice
from sympy import sqrt_mod
def A116260_gen(): # generator of terms
for j in count(0):
b = 10**j
a = b*10+1
for k in sorted(sqrt_mod(0, a, all_roots=True))+[a]:
if a*(b+4) <= k**2 < a*(a+3):
yield k2


CROSSREFS



KEYWORD

nonn,base


AUTHOR



STATUS

approved



