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 1-6 of 6 results.

A116172 Numbers k such that k concatenated with k+2 gives the product of two numbers which differ by 5.

Original entry on oeis.org

2, 74, 59264, 510782, 906902, 81790664, 92776472, 10876856041862, 11796926254874, 18332259798794, 18388650720624, 32624670587648, 32699883214248, 43103618706398, 44916698243804, 66132258426302
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Comments

Also numbers k such that k concatenated with k+6 gives the product of two numbers which differ by 3.
Also numbers k such that k concatenated with k+8 gives the product of two numbers which differ by 1.
If k+2 and k-4 have the same number of digits, then k is also in A116132 because k//k+2 = 10^d*k + k + 2 = m*(m+5) then implies k//k-4 = 10^d*k + k - 4 = m*(m+5) - 6 = (m-1)*(m+6). - R. J. Mathar, Aug 10 2008

Examples

			92776472//92776474 = 96320542 * 96320547, where // denotes concatenation.
92776472//92776480 = 96320544 * 96320545.
92776472//92776478 = 96320543 * 96320546.
		

Crossrefs

Extensions

Edited by N. J. A. Sloane, Apr 15 2007

A116205 Numbers k such that k concatenated with k+7 gives the product of two numbers which differ by 3.

Original entry on oeis.org

1, 81, 1353, 3997, 7723, 23761, 26271, 76771, 1415683, 3890571, 8495497, 1066870443, 1239366513, 4198438981, 4534273891, 6502317141, 6918679731, 2199164200036329043, 2820114781174460091, 5500888421709400741
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Comments

Also numbers k such that k concatenated with k+9 gives the product of two numbers which differ by 1.
Also numbers k such that k concatenated with k-3 gives the product of two numbers which differ by 7.

Crossrefs

Extensions

Edited by N. J. A. Sloane, Apr 13 2007

A116133 Numbers k such that k concatenated with k-4 gives the product of two numbers which differ by 9.

Original entry on oeis.org

64, 1876, 3214, 8776, 17227120144584448354, 19391087990479091186, 21557280540171744040, 23970390649400564404, 26051259424903756364, 28697643366269876506, 31320461807899711990, 34215988012600009664
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Comments

Also numbers k such that k concatenated with k+4 gives the product of two numbers which differ by 7.
Since k*(10^j+1) + 4 = m*(m+7) iff k*(10^j+1) - 4 = m*(m+7) - 8 = (m-1)*(m+8) = M*(M+9) this is trivially the same sequence. - N. J. A. Sloane, Apr 11 2007

Examples

			8776//8772 = 9364 * 9373, where // denotes concatenation. Also 8776//8780 = 9365 * 9372.
		

Crossrefs

Extensions

Edited by N. J. A. Sloane, Apr 11 2007

A116119 Numbers k such that k concatenated with k-6 gives the product of two numbers which differ by 7.

Original entry on oeis.org

96, 150, 186, 324, 376, 666, 996, 2046, 3000, 9996, 82650, 99996, 100384, 466716, 999996, 1322316, 4049584, 9999996, 67820074, 99999996, 110003884, 135734074, 156502836, 196043286, 213017754, 238849000, 261405396, 289940826
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Examples

			9802960500//9802960494 = 9900990099 * 9900990106, where // denotes concatenation.
		

Crossrefs

A116131 Numbers k such that k concatenated with k-4 gives the product of two numbers which differ by 6.

Original entry on oeis.org

20, 31, 14564, 38239, 69919, 120395, 426436, 902596, 7478020, 9090220, 6671332084, 8114264059, 8482227259, 9900250996, 2244338786836, 2490577152964, 2509440638591, 2769448208395, 7012067592220
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Examples

			9900250996//9900250992 = 9950000498 * 9950000504, where // denotes concatenation.
		

Crossrefs

A116263 n times n+7 gives the concatenation of two numbers m and m-4.

Original entry on oeis.org

83, 76980, 714687, 952311, 90438188, 96320541, 32980078899026, 34346653774235, 42816188292270, 42881990066485, 57118009933509, 57183811707724, 65653346225759, 67019921100968, 81321742742207
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Examples

			96320541 * 96320548 = 92776472//92776468, where // denotes
concatenation.
		

Crossrefs

Showing 1-6 of 6 results.