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.

A061839 a(n+1) is the smallest square ending with a(n), initial term is 5.

Original entry on oeis.org

5, 25, 225, 1225, 81225, 16281225, 7077116281225, 1642681227077116281225, 228822983661635570881642681227077116281225, 976324672198183536165095004791768497036228822983661635570881642681227077116281225
Offset: 1

Views

Author

Amarnath Murthy, May 29 2001

Keywords

Links

Crossrefs

Cf. A050634, A065689, A065780, A065781, A050636, A050638.

Extensions

Corrected and extended by Frank Ellermann, Jun 04 2001
More terms from Ulrich Schimke (ulrschimke(AT)aol.com), Dec 18 2001
Edited by N. J. A. Sloane, Apr 29 2007
First term prepended by Derek Orr, Dec 27 2013

A050639 a(1) = 3; a(n+1)^2 is next smallest square ending with a(n)^2.

Original entry on oeis.org

3, 7, 43, 1293, 154957, 20214998707, 118659019449999845043, 5566692951015284052000000000020214998707, 21637689578064053873124753714430240419600000000000000000000118659019449999845043
Offset: 1

Views

Author

Patrick De Geest, Jul 15 1999

Keywords

Crossrefs

Cf. A050638, A048562, A050631.

Extensions

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

A050632 a(n+1) is next smallest nontrivial square containing a(n) as a substring, initial term is 9.

Original entry on oeis.org

9, 49, 1849, 18496, 103184964, 7383508103184964, 544680602158273835081031849649
Offset: 1

Views

Author

Patrick De Geest, Jul 15 1999

Keywords

Crossrefs

Starting with a(2)=49, the sequence is identical to A050630.
Cf. A050633, A048561, A050638.

Formula

a(n) = A050633(n)^2.

Extensions

a(7) from Max Alekseyev, Feb 15 2012

A065785 a(1) = 49; 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

49, 1849, 1671849, 24011671849, 408646172724011671849, 14079962896835441528408646172724011671849, 30988070410883251650062468506470600085614079962896835441528408646172724011671849
Offset: 1

Views

Author

Klaus Brockhaus, Nov 19 2001

Keywords

Comments

a(n) = A050638(n+1) for n >= 1.

Crossrefs

Cf. A050634, A050638, A065689, A065786, A065787.

A065807 Squares with a smaller square as final digits.

Original entry on oeis.org

49, 64, 81, 100, 121, 144, 169, 225, 289, 324, 361, 400, 441, 484, 529, 625, 729, 784, 841, 900, 961, 1024, 1089, 1225, 1369, 1444, 1521, 1600, 1681, 1764, 1849, 1936, 2025, 2116, 2209, 2304, 2401, 2500, 2601, 2704, 2809, 2916, 3025, 3136, 3249, 3364
Offset: 1

Views

Author

Klaus Brockhaus, Nov 22 2001

Keywords

Links

Crossrefs

A065808 gives the corresponding square roots.
Cf. A038678.
Cf. A065689, A050634, A050636, A050638, A065776, A061839, A065782, A065785, A065788, A065791.

Programs

  • Mathematica
    ds[n_] := NestWhileList[FromDigits[Rest[IntegerDigits[#]]] &, n, # > 9 &]; Select[Range[4, 58]^2, Or @@ IntegerQ /@ Sqrt[Rest[ds[#]]] &] (* Jayanta Basu, Jul 10 2013 *)
  • PARI
    a065807(m) = local(a, b, d, j, k, n); for(k=1, m, a=length(Str(n))-1; b=1; j=1; n=k^2; while(b, d=divrem(n, 10^j); if(d[1]>0&&issquare(d[2]), b=0; print1(n, ", "), if(j
  • PARI
    isokend(n) = my(p=10); for(k=1, #Str(n)-1, if (issquare(n % p), return (1)); p*=10);
isok(n) = issquare(n) && isokend(n); \\ Michel Marcus, Mar 17 2020

Extensions

Changed offset from 0 to 1 by Vincenzo Librandi, Sep 24 2013
Showing 1-6 of 6 results.

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

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