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A116267 Numbers k such that k*(k+4) gives the concatenation of two numbers m and m-3. 6
8, 98, 426, 571, 725, 844, 998, 7808, 9998, 36363, 63634, 99998, 326732, 673265, 999998, 4545452, 5454545, 9999998, 47058821, 52941176, 99999998, 331983805, 332667332, 384615384, 422892896, 475524475, 524475522, 577107101, 615384613, 667332665, 668016192, 719964244 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
PROG
(Python)
from itertools import count, islice
from sympy import sqrt_mod
def A116267_gen(): # generator of terms
for j in count(0):
b = 10**j
a = b*10+1
for k in sorted(sqrt_mod(1, a, all_roots=True)):
if a*(b+3) <= k**2-1 < a*(a+2):
yield k-2
A116267_list = list(islice(A116267_gen(), 20)) # Chai Wah Wu, Feb 19 2024
CROSSREFS
Sequence in context: A083182 A302277 A302727 * A183334 A196327 A116130
KEYWORD
nonn,base
AUTHOR
Giovanni Resta, Feb 06 2006
EXTENSIONS
a(29)-a(32) from Chai Wah Wu, Feb 19 2024
STATUS
approved

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Last modified April 19 19:02 EDT 2024. Contains 371798 sequences. (Running on oeis4.)