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.

A116180 Numbers k such that k concatenated with k+3 gives the product of two numbers which differ by 7.

Original entry on oeis.org

7137, 7767, 47783068991048776635, 48797525371338932241, 55658688122404752991, 56753136503494828605, 85555875266989354735, 86911515887391841491, 95992713077544748491, 97428345698747155255
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Comments

Also numbers k such that k concatenated with k-5 gives the product of two numbers which differ by 9.
Also numbers k such that k concatenated with k+9 gives the product of two numbers which differ by 5.

Examples

			7767//7770 = 8810 * 8817, where // denotes concatenation.
7767//7762 = 8809 * 8818.
7767//7776 = 8811 * 8816.
		

Crossrefs

Extensions

Edited by N. J. A. Sloane, Apr 12 2007

A116125 Numbers k such that k concatenated with k-5 gives the product of two numbers which differ by 6.

Original entry on oeis.org

7, 97, 205, 300, 477, 732, 997, 1920, 3157, 9997, 52896, 99997, 120085, 427020, 999997, 8264460, 9999997, 88581312, 99999997, 112000885, 112917765, 143075580, 152863360, 193537077, 233788192, 266755221, 313680096
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Comments

Also numbers k such that k concatenated with itself gives the product of two numbers which differ by 4.

Examples

			6786111717//6786111712 = 8237785936 * 8237785942, where // denotes concatenation.
		

Crossrefs

Extensions

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

A116173 Numbers k such that k concatenated with k+2 gives the product of two numbers which differ by 6.

Original entry on oeis.org

6752089, 6448802889351008245, 18894512461523256139943105859903480218905, 31958875438439894736354375209245786214798
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Comments

Also numbers k such that k concatenated with k+7 gives the product of two numbers which differ by 4.
If k+2 and k-5 have the same number of digits, the k is also in A116126, because k//k+2 = 10^d*k + k + 2 = m*(m+6) then implies a representation k//k-5 = 10^d*k + k - 5 = m*(m+6)-7 = (m-1)*(m+7). - R. J. Mathar, Aug 10 2008

Examples

			6752089//6752091 = 8217107 * 8217113, where // denotes concatenation.
6752089//6752096 = 8217108 * 8217112.
		

Crossrefs

Extensions

Edited by N. J. A. Sloane, Apr 12 2007

A116257 n times n+8 gives the concatenation of two numbers m and m-5.

Original entry on oeis.org

7, 8217106, 8030443878983905980, 43467818511541680701794365325328847002050, 56532181488458319298205634674671152997943
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Examples

			8217106 * 8217114 = 6752089//6752084, where // denotes
concatenation.
		

Crossrefs

A116113 Numbers k such that k concatenated with k-7 gives the product of two numbers which differ by 8.

Original entry on oeis.org

95, 216, 287, 515, 675, 995, 1175, 4320, 9995, 82640, 99995, 960795, 999995, 1322312, 4049591, 9999995, 16955015, 34602080, 99999995, 171010235, 181964891, 183673467, 187160072, 321920055, 326530616, 328818032
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Examples

			8533818720//8533818713 = 9237867023 * 9237867031, where // denotes concatenation.
		

Crossrefs

A116139 Numbers k such that k concatenated with k-3 gives the product of two numbers which differ by 8.

Original entry on oeis.org

43, 20440836, 30017751, 61336887, 52400871197755334426147587, 53651708763838760619655612, 56652002793835820319625612, 57952296063256269823192087, 17684775866714240650923831481623
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Examples

			61336887//61336884 = 78317866 * 78317874, where // denotes concatenation.
		

Crossrefs

Showing 1-6 of 6 results.