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 1-10 of 11 results. Next

A115429 Numbers k such that the concatenation of k with k+8 gives a square.

Original entry on oeis.org

6001, 6433, 11085116, 44496481, 96040393, 115916930617, 227007035017, 274101929528, 434985419768, 749978863753, 996004003993, 1365379857457948, 1410590590957816, 1762388551055953, 2307340946901148, 2700383162251217
Offset: 1

Views

Author

Giovanni Resta, Jan 24 2006

Keywords

Comments

Also numbers k such that k concatenated with k+7 gives the product of two numbers which differ by 2.
Also numbers k such that k concatenated with k+4 gives the product of two numbers which differ by 4.
Also numbers k such that k concatenated with k-1 gives the product of two numbers which differ by 6.
Also numbers k such that k concatenated with k-8 gives the product of two numbers which differ by 8.

Examples

			6001//6009 = 7747^2, where // denotes concatenation.
96040393//96040400 = 98000200 * 98000202.
96040393//96040397 = 98000199 * 98000203.
96040393//96040392 = 98000198 * 98000204.

Crossrefs

Cf. A030465, A102567, A115426, A115437, A115428, A115430, A115431, A115432, A115433, A115434, A115435, A115436, A115440.
Cf. A116107, A116109, A116113, A116239.
Cf. A116205, A115430, A116335, A116185, A116187, A116317.
Cf. A116131, A116112, A116152, A116159, A116282.

Extensions

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

A116099 Numbers k such that k concatenated with k-9 gives the product of two numbers which differ by 7.

Original entry on oeis.org

69, 59898667, 79493157, 13412927190959690154913903, 14163000698458955079906403, 38895475965785687555173929, 40165600438484442828161229, 74294440818366638194239027
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Comments

Also numbers k such that k concatenated with k-3 gives the product of two numbers which differ by 5.
Also numbers k such that k concatenated with k+1 gives the product of two numbers which differ by 3.
Also numbers k such that k concatenated with k+3 gives the product of two numbers which differ by 1.

Examples

			79493157//79493154 = 89158933 * 89158938, where // denotes concatenation.
79493157//79493158 = 89158934 * 89158937.
79493157//79493160 = 89158935 * 89158936.
79493157//79493148 = 89158932 * 89158939.

Crossrefs

Cf. A116098, A116193, A116107, A116230, A116130, A116136, A116205, A116107, A116268.
Cf. A115426, A115428, A116171, A116296, A116170, A116177, A116307.

Extensions

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

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

Cf. A116158, A116171, A116173, A116179, A116303.
Cf. A116185, A115430, A116205, A116343, A116200, A116330.

Extensions

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

A116193 Numbers k such that k concatenated with k+5 gives the product of two numbers which differ by 5.

Original entry on oeis.org

11, 45, 18281, 32769, 56891, 180689, 330539, 959481, 1850201, 3247409, 4940219, 2425563239, 2575561739, 6003563495, 7245212645, 7770160145, 4983798265289, 5049762270381, 5534298528989, 5603798594169, 21894082450101
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 3. For proof that this is the same sequence compare A116133.
Also numbers k such that k concatenated with k-9 gives the product of two numbers which differ by 9.

Examples

			7770160145//7770160136 = 8814851183 * 8814851192, where // denotes concatenation.

Crossrefs

Cf. A116205, A116187, A116349.
Cf. A116179, A115430, A116194, A116200, A116324.
Cf. A116099, A116109, A116231.

Extensions

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

Cf. A116159, A116172, A116174, A116187, A116304.
Cf. A115430, A116205, A116207, A116187, A116337.

Extensions

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

A116132 Numbers k such that k concatenated with k-4 gives the product of two numbers which differ by 7.

Original entry on oeis.org

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

Examples

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

Crossrefs

Cf. A116119, A116131, A116133, A116205, A116263.

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

Cf. A116126, A116205, A116140, A116146, A116270.

A116152 Numbers k such that k concatenated with k-1 gives the product of two numbers which differ by 7.

Original entry on oeis.org

9, 11, 45, 18281, 32769, 56891, 180689, 330539, 959481, 1850201, 3247409, 4940219, 2425563239, 2575561739, 6003563495, 7245212645, 7770160145, 4983798265289, 5049762270381, 5534298528989, 5603798594169
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Crossrefs

Cf. A116205, A115429, A116153, A116160, A116283.

A116269 Numbers k such that k*(k+7) gives the concatenation of two numbers m and m-3.

Original entry on oeis.org

87, 3675, 6319, 8785, 48742, 51252, 87616, 3762553, 6237441, 9217099, 3266298273, 3520463763, 6479536231, 6733701721, 8063694647, 8317860137, 4689524709430934473, 5310475290569065521, 7416797436703661746
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Crossrefs

Cf. A116205, A116263, A116268, A116270, A116283.

A116336 n times n+3 gives the concatenation of two numbers m and m+7.

Original entry on oeis.org

3, 89, 3677, 6321, 8787, 48744, 51254, 87618, 3762555, 6237443, 9217101, 3266298275, 3520463765, 6479536233, 6733701723, 8063694649, 8317860139, 4689524709430934475, 5310475290569065523, 7416797436703661748
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Crossrefs

Cf. A116205, A116330, A116335, A116337, A116349.
Showing 1-10 of 11 results. Next

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

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