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 13 results. Next

A065689 a(1) = 0; for n > 1, a(n) is the smallest square > a(n-1) with a(n-1) forming its final digits.

Original entry on oeis.org

0, 100, 8100, 168100, 146168100, 22086146168100, 3107111332622086146168100, 3651070583444637156963107111332622086146168100, 26849677386445867852272270902339560405490043651070583444637156963107111332622086146168100
Offset: 1

Views

Author

Klaus Brockhaus, Nov 17 2001

Keywords

Comments

a(n) = 100*A050634(n-1) for n > 1.

Crossrefs

Cf. A050634, A050635, A061359, A065690, A065691.

A065690 a(1) = 0; for n > 1, a(n) is the square root of the smallest square > a(n-1)^2 with a(n-1)^2 forming its final digits.

Original entry on oeis.org

0, 10, 90, 410, 12090, 4699590, 1762700012090, 60424089429999995300410, 163858711658690481272000000000001762700012090, 284443295612274221167414335130587074570377999999999999999999999939575910570000004699590
Offset: 1

Views

Author

Klaus Brockhaus, Nov 17 2001

Keywords

Comments

a(n) = 10*A050635(n-1) for n > 1; a(n) = sqrt(A065689(n)).

Crossrefs

Cf. A050634, A050635, A061359, A065689, A065691.

A065691 a(1) = 0; for n > 1, a(n) is the smallest integer > 0 such that the concatenation a(n)a(n-1)...a(2)a(1) is a square.

Original entry on oeis.org

0, 10, 8, 16, 146, 22086, 31071113326, 365107058344463715696, 2684967738644586785227227090233956040549004, 809079884187716191997158821357206898310718837487307207657194711477350102495950972665
Offset: 1

Views

Author

Klaus Brockhaus, Nov 17 2001

Keywords

Comments

a(n) = A061359(n-1) for n > 2.

Crossrefs

Cf. A050634, A050635, A061359, A065689, A065690.

A061361 a(1) = 4; a(n) = least number such that the concatenation a(n)a(n-1)...a(2)a(1) is a square.

Original entry on oeis.org

4, 6, 17, 604, 9612, 85848855, 109457393440691436, 16484027824615378535694780556419522, 2537811713051483817817710620248313487995814710180147690293469081793581
Offset: 1

Views

Author

Amarnath Murthy, Apr 28 2001

Keywords

Examples

			a(3)a(2)a(1) = 1764 = 42^2, a(4)a(3)a(2)a(1) = 6041764 = 2458^2, a(5)a(4)a(3)a(2)a(1) = 8584885596126041764 = 2929997542^2.

Crossrefs

Cf. A050636, A050637, A061359, A061363.

Extensions

Corrected by Larry Reeves (larryr(AT)acm.org), May 07 2001
More terms from Ulrich Schimke (ulrschimke(AT)aol.com), Nov 06 2001

A061363 a(1) = 9; a(n) = least number such that the concatenation a(n)a(n-1)...a(2)a(1) is a square.

Original entry on oeis.org

9, 4, 18, 167, 2401, 4086461727, 14079962896835441528, 309880704108832516500624685064706000856, 4681896102766617737298881383797502847166028831212571921983062786215145771871779
Offset: 1

Views

Author

Amarnath Murthy, Apr 28 2001

Keywords

Examples

			a(3)a(2)a(1) = 1849 = 43^2, a(4)a(3)a(2)a(1) = 1671849 = 1293^2.

Crossrefs

Cf. A050638, A050639, A061359, A061361.

Extensions

Corrected by Larry Reeves (larryr(AT)acm.org), May 07 2001
More terms from Ulrich Schimke (ulrschimke(AT)aol.com), Nov 06 2001

A061491 a(1) = 1, a(n) = least number such that the concatenation a(n)a(n-1)...a(1) is a cube.

Original entry on oeis.org

1, 133, 100330363, 100000000300330000300660363, 100000000000000000000000000300000000300330000000000000300000000600660000300660363
Offset: 1

Views

Author

Amarnath Murthy, May 06 2001

Keywords

Examples

			a(1) = 1, a(2) = 133, a(2)a(1) = 1331 = 11^3.

Links

Crossrefs

Cf. A061359, A061361, A061363.

Programs

  • Maple
    f:= proc(n) local j; 10^(-3^(n-1)/2-1)*(add(10^(3^j/2),j=0..n-1)^3 - add(10^(3^j/2),j=0..n-2)^3) end proc:
seq(f(n),n=1..5); # Robert Israel, Jun 17 2024

Formula

a(n) = 10^(-3^(n-1)/2-1)*(Sum_{j=0..n-1}(10^(3^j/2))^3 - Sum_{j=0..n-2} (10^(3^j/2))^3). - Robert Israel, Jun 17 2024

Extensions

More terms from Ulrich Schimke (ulrschimke(AT)aol.com), Nov 06 2001
Corrected by Robert Israel, Jun 17 2024

A065778 a(1) = 16; for n > 1, a(n) is the smallest integer > 0 such that the concatenation a(n)a(n-1)...a(2)a(1) is a square.

Original entry on oeis.org

16, 21, 602, 9919, 201825782, 786148373230451374, 222497947677972243238266280556039145, 689281060145549220555862860288211510118547777224654163905516661857896088
Offset: 1

Views

Author

Klaus Brockhaus, Nov 19 2001

Keywords

Crossrefs

Cf. A061359, A065691, A065776, A065777.

Extensions

More terms from Ulrich Schimke (ulrschimke(AT)aol.com), Dec 18 2001

A065781 a(1) = 25; for n > 1, a(n) is the smallest integer > 0 such that the concatenation a(n)a(n-1)...a(2)a(1) is a square.

Original entry on oeis.org

25, 2, 1, 8, 162, 70771, 164268122, 22882298366163557088, 976324672198183536165095004791768497036, 67395729561035485747722358417684895847812434249174374011671902126543092988774
Offset: 1

Views

Author

Klaus Brockhaus, Nov 19 2001

Keywords

Crossrefs

Cf. A061359, A065691, A061839, A065780.

Extensions

More terms from Ulrich Schimke (ulrschimke(AT)aol.com), Dec 18 2001

A065784 a(1) = 36; for n > 1, a(n) is the smallest integer > 0 such that the concatenation a(n)a(n-1)...a(2)a(1) is a square.

Original entry on oeis.org

36, 19, 603, 155636, 4615730086, 8967254090271143, 56096202719698239565812734781810166, 45033337806374635393337595037647446798889403018884984457350362192958678
Offset: 1

Views

Author

Klaus Brockhaus, Nov 19 2001

Keywords

Crossrefs

Cf. A061359, A065691, A065782, A065783.

Extensions

More terms from Ulrich Schimke (ulrschimke(AT)aol.com), Dec 18 2001

A065787 a(1) = 49; for n > 1, a(n) is the smallest integer > 0 such that the concatenation a(n)a(n-1)...a(2)a(1) is a square.

Original entry on oeis.org

49, 18, 167, 2401, 4086461727, 14079962896835441528, 309880704108832516500624685064706000856, 4681896102766617737298881383797502847166028831212571921983062786215145771871779
Offset: 1

Views

Author

Klaus Brockhaus, Nov 19 2001

Keywords

Comments

a(n) = A061363(n+1) for n > 1.

Crossrefs

Cf. A061359, A061363, A065691, A065785, A065786.
Showing 1-10 of 13 results. Next

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