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 1-9 of 9 results.

A115430 Numbers k such that the concatenation of k with k+9 gives a square.

Original entry on oeis.org

216, 287, 515, 675, 1175, 4320, 82640, 960795, 1322312, 4049591, 16955015, 34602080, 171010235, 181964891, 183673467, 187160072, 321920055, 326530616, 328818032, 343942560, 470954312, 526023432, 528925616, 534830855
Offset: 1

Views

Author

Giovanni Resta, Jan 24 2006

Keywords

Comments

Also numbers k such that k concatenated with k+8 gives the product of two numbers which differ by 2.
Also numbers k such that k concatenated with k+5 gives the product of two numbers which differ by 4.

Examples

			82640_82649 = 90907^2.

Crossrefs

Cf. A030465, A102567, A115426, A115437, A115428, A115429, A115431, A115432, A115433, A115434, A115435, A115436, A115441.
Cf. A116172, A116168, A116344, A116112, A116193, A116173, A116323.

Extensions

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

A116169 Numbers k such that k concatenated with k+1 gives the product of two numbers which differ by 9.

Original entry on oeis.org

9, 49, 1166975893986638437392162264780939, 1411174268292962563778302427727571, 1860631503683565562655236868895135
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 7.

Examples

			49//50 = 66 * 75, where // denotes concatenation.
49//58 = 67 * 74.

Crossrefs

Cf. A116162, A116168, A116175, A116300.
Cf. A116215, A116174, A116223, A116353.

Extensions

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

A116174 Numbers k such that k concatenated with k+2 gives the product of two numbers which differ by 8.

Original entry on oeis.org

1143, 4382, 4943, 24941511, 25058558, 94090583, 616729341438, 638432642423, 978717194478, 994009005983, 1636200161363007, 1710661666314798, 1805005185949007, 1906479843038783, 1986790648039982, 3072104679280383
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 6.

Examples

			94090583//94090585 = 97000297 * 97000305, where // denotes concatenation.
94090583//94090592 = 97000298 * 97000304.

Crossrefs

Cf. A116168, A116173, A116175, A116181, A116305.
Cf. A116180, A116169, A116352.

Extensions

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

A116167 Numbers k such that k concatenated with k+1 gives the product of two numbers which differ by 7.

Original entry on oeis.org

7, 493, 607, 629, 757, 17927, 33247, 93869, 19467217, 31223879, 72757727, 13454739732766891651472740499, 40093333713615672956030023507, 48089152118689474641229584727, 66424317743191484432891678269
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Examples

			72757727//72757728 = 85298137 * 85298144, where // denotes concatenation.

Crossrefs

Cf. A116160, A115428, A116168, A116180, A116298.

A116345 Numbers k such that k*(k+6) gives the concatenation of two numbers m and m+8.

Original entry on oeis.org

41, 54, 40354308, 59645687, 39704957106129738595969799927611, 44505281604832422780051712184760, 45053875613995255103944518907120, 54946124386004744896055481092875, 55494718395167577219948287815235, 60295042893870261404030200072384, 68683652917306421895276391964227
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Examples

			59645687 * 59645693 = 35576083//35576091, where // denotes concatenation.

Links

Crossrefs

Cf. A116168, A116339, A116344, A116346, A116352.

Programs

  • Maple
    f:= proc(d) local R;
   R:= map(rhs@op,{msolve(x^2=17,10^d+1)});
   R:= map(t -> (t-3) mod (10^d+1), R);
   op(select(proc(t) local m; m:= (t*(t+6)-8)/(10^d+1)+8; m >= 10^(d-1) and m < 10^d end proc, R));
end proc;
sort(convert({seq(f(i),i=1..50)},list)); # Robert Israel, Jan 17 2017

Extensions

More terms from Robert Israel, Jan 17 2017

A116161 Numbers k such that k concatenated with itself gives the product of two numbers which differ by 8.

Original entry on oeis.org

3, 93, 145, 384, 505, 820, 993, 7680, 9993, 20665, 29748, 99993, 480340, 999993, 6694209, 9999993, 77854665, 99999993, 107541513, 109342209, 132231408, 174990384, 183673473, 213017748, 289940833, 326530608, 338353345
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Crossrefs

Cf. A116146, A116160, A116162, A116168, A116292.

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

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Crossrefs

Cf. A116194, A116207, A116209, A116168, A116339.

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

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Crossrefs

Cf. A116209, A116168, A116216, A116169, A116346.

A116299 n times n+8 gives the concatenation of two numbers m and m+1.

Original entry on oeis.org

40, 53, 40354307, 59645686, 39704957106129738595969799927610, 44505281604832422780051712184759, 45053875613995255103944518907119, 54946124386004744896055481092874, 55494718395167577219948287815234
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Examples

			59645686 * 59645694 = 35576083//35576084, where // denotes
concatenation.

Crossrefs

Cf. A116168, A116292, A116298, A116300, A116305.
Showing 1-9 of 9 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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