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.

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.

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

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.

A065776 a(n+1) is the next smallest square ending with a(n), initial term is 6.

Original entry on oeis.org

6, 16, 2116, 6022116, 99196022116, 20182578299196022116, 78614837323045137420182578299196022116, 22249794767797224323826628055603914578614837323045137420182578299196022116
Offset: 1

Views

Author

Klaus Brockhaus, Nov 19 2001

Keywords

Crossrefs

Cf. A050634, A065689, A065777, A065778.

Extensions

More terms from Ulrich Schimke (ulrschimke(AT)aol.com), Dec 18 2001
First term prepended by Derek Orr, Dec 27 2013

A065782 a(1) = 36; 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

36, 1936, 6031936, 1556366031936, 46157300861556366031936, 896725409027114346157300861556366031936, 56096202719698239565812734781810166896725409027114346157300861556366031936
Offset: 1

Views

Author

Klaus Brockhaus, Nov 19 2001

Keywords

Crossrefs

Cf. A050634, A065689, A065783, A065784.

Extensions

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

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.

A065788 a(1) = 64; 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

64, 1764, 6041764, 96126041764, 8584885596126041764, 1094573934406914368584885596126041764, 164840278246153785356947805564195221094573934406914368584885596126041764
Offset: 1

Views

Author

Klaus Brockhaus, Nov 19 2001

Keywords

Comments

a(n) = A050636(n+1) for n >= 1.

Crossrefs

A050634, A050636, A065689, A065789, A065790.

Programs

  • Mathematica
    nxt[n_]:=Module[{k=1},While[!IntegerQ[Sqrt[k*10^IntegerLength[n]+n]],k++];k*10^IntegerLength[n]+n]; NestList[nxt,64,6] (* Harvey P. Dale, Dec 14 2019 *)

A065791 a(1) = 81; 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

81, 1681, 1461681, 220861461681, 31071113326220861461681, 36510705834446371569631071113326220861461681, 268496773864458678522722709023395604054900436510705834446371569631071113326220861461681
Offset: 1

Views

Author

Klaus Brockhaus, Nov 19 2001

Keywords

Comments

a(n) = A050634(n+1) for n >= 1.

Crossrefs

Cf. A050634, A065689, A065792, A064793.

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 1-9 of 9 results.

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

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