A116147
Numbers k such that k concatenated with k-2 gives the product of two numbers which differ by 9.
Original entry on oeis.org
4962, 237412345332, 262912791034, 468307643502
Offset: 1
4962//4960 = 7040 * 7049, where // denotes concatenation.
A116208
Numbers k such that k concatenated with k+7 gives the product of two numbers which differ by 6.
Original entry on oeis.org
145, 384, 505, 820, 7680, 20665, 29748, 480340, 6694209, 77854665, 107541513, 109342209, 132231408, 174990384, 183673473, 213017748, 289940833, 326530608, 338353345, 404958673, 448003540, 451671060, 478271265
Offset: 1
A116210
Numbers k such that k concatenated with k+7 gives the product of two numbers which differ by 8.
Original entry on oeis.org
73, 101, 466, 577, 913, 938, 1027699544347561123497066503878337002, 1043891904746431592729642732987859418, 1406975496023772119400647610836667853, 3905041089422306453928649115284570106, 4582028691256280367677282506239892877, 4616148891509946292221374856300250093
Offset: 1
938//945 = 965 * 973, where // denotes concatenation.
-
from itertools import count, islice
from sympy import sqrt_mod
def A116210_gen(): # generator of terms
for j in count(0):
b = 10**j
a = b*10+1
for k in sorted(sqrt_mod(23,a,all_roots=True)):
if a*(b-7) <= k**2-23 < a*(a-8) and k>4:
yield (k**2-23)//a
A116210_list = list(islice(A116210_gen(),10)) # Chai Wah Wu, Feb 22 2024
A116215
Numbers k such that k concatenated with k+8 gives the product of two numbers which differ by 7.
Original entry on oeis.org
92, 180, 332, 486, 536, 9720, 13220, 40502, 941486, 2066120, 2975202, 77854680, 123250136, 162423540, 243964010, 256109750, 356387462, 421110162, 542936282, 547361900, 587114192, 591715970, 685172036, 734693886
Offset: 1
A116340
n times n+7 gives the concatenation of two numbers m and m+7.
Original entry on oeis.org
2, 33, 61, 805, 4779, 5215, 7407, 48208887, 51791107, 77620652, 4291816089, 4482541431, 5517458563, 5708183905, 9036996877, 9737360644, 3579205562000136225339579332, 3939042613182345526485238180
Offset: 1
Showing 1-5 of 5 results.
Comments