A116260
n times n+4 gives the concatenation of two numbers m and m-4.
Original entry on oeis.org
9, 99, 999, 9999, 99999, 999999, 9999999, 99999999, 999999999, 9999999999, 36363636362, 45454545453, 54545454544, 63636363635, 72727272726, 81818181817, 90909090908, 99999999999, 999999999999, 9999999999999
Offset: 1
99999999 * 100000003 = 100000001//99999997, where // denotes concatenation.
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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 k-2
A116260_list = list(islice(A116260_gen(),20)) # Chai Wah Wu, Feb 19 2024
A116248
n times n+4 gives the concatenation of two numbers m and m-6.
Original entry on oeis.org
7310, 8989, 32522, 67475, 76566, 4891728, 5108269, 8528092, 71588334, 98999899, 399659933005, 600340066992, 723627738225, 877712329766, 998999998999, 3485626998112, 3787100274612, 6212899725385, 6514373001885
Offset: 1
98999899 * 98999903 = 98009803//98009797, where // denotes
concatenation.
A116253
n times n+3 gives the concatenation of two numbers m and m-5.
Original entry on oeis.org
96012, 3812029082958589067221817215313, 6187970917041410932778182784685, 3189731673290266386838927279556315881
Offset: 1
96012 * 96015 = 92185//92180, where // denotes concatenation.
A116255
n times n+5 gives the concatenation of two numbers m and m-5.
Original entry on oeis.org
76, 80917, 91807, 326508, 475023, 524973, 673488, 4323775, 4767130, 5232866, 5676221, 4083911139, 4975000248, 5024999748, 5916088857, 9503960494, 9604950394, 4186904462790, 4313465946773, 5686534053223, 5813095537206
Offset: 1
Showing 1-4 of 4 results.