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 1-7 of 7 results.

A167734 Primes that become squares when prefixed with a 1.

Original entry on oeis.org

521, 10889, 23201, 27449, 31769, 36161, 45161, 54449, 78929, 99809, 1148921, 1229201, 1309769, 1431161, 2047841, 2257001, 2299049, 2467961, 2595401, 2680721, 2766329, 2809241, 2895281, 2938409, 3024881, 3329801, 3417569, 3461561
Offset: 1

Views

Author

Claudio Meller, Nov 10 2009

Keywords

Links

Crossrefs

Cf. A167735, A167736, A167737, A167738, A167739, A167740, A167741.

Programs

  • Mathematica
    Select[Prime[Range[1000]], IntegerQ[Sqrt[FromDigits[Join[{1}, IntegerDigits[#]]]]]&] (* G. C. Greubel, Jun 23 2016 *)

Extensions

More terms from Michel Marcus, Aug 05 2013

A167735 Primes that become squares when prefixed with a 2.

Original entry on oeis.org

5, 89, 401, 601, 809, 1609, 2801, 4649, 5281, 6569, 9241, 9929, 14369, 18089, 19961, 21841, 27529, 33289, 41081, 43049, 51001, 61121, 67289, 73529, 79841, 84089, 92681, 94849
Offset: 1

Views

Author

Claudio Meller, Nov 10 2009

Keywords

Links

Crossrefs

Cf. A167734, A167736, A167737, A167738, A167739, A167740, A167741.

Programs

  • Mathematica
    Select[Prime[Range[10000]],IntegerQ[Sqrt[FromDigits[Join[{2},IntegerDigits[#]]]]]&] (* Harvey P. Dale, Dec 16 2010 *)
  • PARI
    \\ terms upto 10^n
upto(n) = {my(sqrt21 = sqrt(2.1), sqrt30 = sqrt(3.0),r,t=0);
for(k=2, n, for(j = ceil((sqrt21 * sqrt(10^k))), floor(sqrt30 * sqrt(10^k)),
r = j^2%10^k; if(isprime(r),t++;print1(r", "))));t} \\ David A. Corneth, Jun 24 2016

A167736 Primes that become squares when prefixed with a 3.

Original entry on oeis.org

61, 4969, 6481, 9601, 23761, 26041, 37561, 68449, 88129, 129361, 179089, 214849, 265249, 301489, 308761, 411409, 455881, 463321, 485689, 508129, 523129, 530641, 659569, 713329, 751969, 829849, 916441, 924361, 948169, 964081, 996001, 1058329, 1147561, 1281649
Offset: 1

Views

Author

Claudio Meller, Nov 10 2009

Keywords

Links

Crossrefs

Cf. A167734, A167735, A167737, A167738, A167739, A167740, A167741.

Programs

  • Mathematica
    Select[Prime[Range[1000000]],IntegerQ[Sqrt[FromDigits[Join[{3}, IntegerDigits[ #]]]]]&] (* Harvey P. Dale, Nov 01 2011 *)
  • PARI
    \\ terms upto 10^n
upto(n) = {my(sqrt31 = sqrt(3.1), sqrt40 = sqrt(4.0), r); for(k=2, n, for(j = ceil((sqrt31 * sqrt(10^k))), floor(sqrt40 * sqrt(10^k)), r = j^2%10^k; if(isprime(r), print1(r", "))))} \\ David A. Corneth, Jun 24 2016

Extensions

More terms from Harvey P. Dale, Nov 01 2011

A167738 Primes that become squares when prefixed with a 5.

Original entry on oeis.org

29, 929, 2441, 3361, 4289, 7121, 8081, 9049, 19841, 34361, 49081, 61001, 76081, 88289, 94441, 112121, 121169, 148361, 193841, 230369, 239521, 276209, 322249, 377761, 414929, 461569, 536609, 564881, 583769, 602689, 621641, 707321, 745609
Offset: 1

Views

Author

Claudio Meller, Nov 10 2009

Keywords

Links

Crossrefs

Cf. A167734, A167735, A167736, A167737, A167739, A167740, A167741.

Programs

  • Mathematica
    Select[Prime[Range[10000]], IntegerQ[Sqrt[FromDigits[Join[{5}, IntegerDigits[#]]]]]&] (* G. C. Greubel, Jun 23 2016 *)

Extensions

More terms from Michel Marcus, Aug 05 2013

A167739 Primes that become squares when prefixed with a 6.

Original entry on oeis.org

241, 1009, 3001, 44809, 67489, 93889, 145441, 195121, 205081, 235009, 285049, 295081, 355441, 416089, 538249, 558721, 620329, 713281, 744409, 817321, 1199329, 1418569, 1481281, 1889689, 1952641, 2520649, 2742241, 3409369, 3504961, 3568729, 3792169, 3952009
Offset: 1

Views

Author

Claudio Meller, Nov 10 2009

Keywords

Links

Crossrefs

Cf. A167734, A167735, A167736, A167737, A167738, A167740, A167741.

Programs

  • Mathematica
    Select[Prime[Range[300000]],IntegerQ[Sqrt[FromDigits[Join[{6}, IntegerDigits[ #]]]]]&] (* Harvey P. Dale, May 05 2012 *)

Extensions

More terms from Harvey P. Dale, May 05 2012

A167740 Primes that become squares when prefixed with a 7.

Original entry on oeis.org

29, 569, 1289, 7841, 62129, 306209, 436529, 502121, 634169, 667361, 935489, 1723961, 1927361, 2131049, 2437121, 2539289, 2948681, 3153809, 3564929, 4080449, 5116889, 5846681, 6160529, 6790169, 7316849, 7845329, 8269409, 8481881, 8694641, 8801129, 9869969
Offset: 1

Views

Author

Claudio Meller, Nov 10 2009

Keywords

Links

Crossrefs

Cf. A167734, A167735, A167736, A167737, A167738, A167739, A167741.

Programs

  • Mathematica
    Select[Prime[Range[10000]], IntegerQ[Sqrt[FromDigits[Join[{7}, IntegerDigits[#]]]]]&] (* G. C. Greubel, Jun 23 2016 *)
  • PARI
    isok(n) = isprime(n) && issquare(n + 7*10^(length(Str(n)))) \\ Michel Marcus, Aug 05 2013
  • PARI
    \\ terms upto 10^n
upto(n) = {my(sqrt71 = sqrt(7.1), sqrt80 = sqrt(8.0),r); for(k=2, n, for(j = ceil((sqrt71 * sqrt(10^k))), floor(sqrt80 * sqrt(10^k)), r = j^2%10^k; if(isprime(r), print1(r", "))))} \\ David A. Corneth, Jun 24 2016

Extensions

More terms from Michel Marcus, Aug 05 2013
Definition modified by Harvey P. Dale, Nov 12 2021

A167741 Primes that become squares when prefixed with an 8.

Original entry on oeis.org

41, 281, 5849, 8209, 11801, 29921, 33569, 51929, 70489, 77969, 128201, 139609, 196769, 219689, 346321, 415801, 450649, 532241, 543929, 602489, 625969, 684809, 743849, 755681, 767521, 922169, 934121, 946081, 958049
Offset: 1

Views

Author

Claudio Meller, Nov 10 2009

Keywords

Comments

Subsequence of primes of A273363. - Michel Marcus, Jun 24 2016

Links

Crossrefs

Cf. A167734, A167735, A167736, A167737, A167738, A167739, A167740.
Cf. A273363.

Programs

  • Mathematica
    Select[Prime[Range[10000]], IntegerQ[Sqrt[FromDigits[Join[{8}, IntegerDigits[#]]]]]&] (* G. C. Greubel, Jun 23 2016 *)
Select[Prime[Range[80000]],IntegerQ[Sqrt[8*10^IntegerLength[#]+#]]&] (* Harvey P. Dale, Jan 29 2023 *)

Extensions

Definition corrected and sequence extended by Michel Marcus, Aug 05 2013
Showing 1-7 of 7 results.

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