cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-4 of 4 results.

A116341 k times k+8 gives the concatenation of two numbers m and m+7.

Original entry on oeis.org

82, 314, 679, 756, 952, 965, 3205775326418807415637845823789043451, 3230931606745075612526180113373983267, 3750967203300732832735999247776048870, 6249032796699267167264000752223951123, 6769068393254924387473819886626016726, 6794224673581192584362154176210956542
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Examples

			965 * 973 = 938//945, where // denotes concatenation, so 965 is a term.
		

Crossrefs

Programs

  • Python
    from itertools import count, islice
    from sympy import sqrt_mod
    def A116341_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-4
    A116341_list = list(islice(A116341_gen(),20)) # Chai Wah Wu, Feb 21 2024

Extensions

a(10)-a(12) from Chai Wah Wu, Feb 21 2024

A116223 Numbers k such that k concatenated with k+9 gives the product of two numbers which differ by 8.

Original entry on oeis.org

136, 399, 600, 744, 8184, 66951, 134199, 401536, 5289264, 12456744, 41868519, 113342199, 115655064, 142598664, 160143051, 206611575, 227626176, 273422475, 297520656, 359785504, 387353899, 435493131, 440015536
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Crossrefs

A116353 Numbers k such that k*(k+7) gives the concatenation of two numbers m and m+9.

Original entry on oeis.org

27, 67, 3416102887775247376839416334668636, 3756559953325598880263233435801765, 4313503800489302411917772257282209
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Examples

			67 * 74 = 49//58, where // denotes concatenation.
		

Crossrefs

A116355 n times n+9 gives the concatenation of two numbers m and m+9.

Original entry on oeis.org

44, 48, 32182682, 32523192, 67476800, 67817310, 35810391829060641485878662, 41417330943216586236893607, 58582669056783413763106385, 64189608170939358514121330, 87098712900990098712901285
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Examples

			67817310 * 67817319 = 45991881//45991890, where // denotes concatenation.
		

Crossrefs

Showing 1-4 of 4 results.