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.

A267769 Numbers whose base-9 representation is a square when read in base 10.

Original entry on oeis.org

0, 1, 4, 15, 23, 33, 58, 73, 81, 100, 121, 185, 213, 265, 298, 324, 361, 400, 474, 509, 555, 643, 685, 751, 861, 914, 1093, 1153, 1215, 1288, 1354, 1481, 1554, 1705, 1783, 1863, 1945, 2029, 2210, 2301, 2488, 2584, 2673, 2773, 2875, 3101, 3210, 3424, 3538, 3682, 3802, 4038, 4154, 4281, 4450
Offset: 1

Views

Author

M. F. Hasler, Jan 20 2016

Keywords

Comments

Trivially includes powers of 81, since 81^k = 100..00_9 = 10^(2k) when read in base 10. Moreover, for any a(n) in the sequence, 81*a(n) is also in the sequence. One could call "primitive" the terms not of this form. These primitive terms include the subsequence 81^k + 2*9^k + 1 = (9^k+1)^2, k > 0, which yields A033934 when written in base 9.

Crossrefs

Cf. A267763 - A267768 for bases 3 through 8. The base-2 analog is A000302 = powers of 4.

Programs

  • Mathematica
    Select[Range[0, 5000], IntegerQ@ Sqrt@ FromDigits@ IntegerDigits[#, 9] &] (* Michael De Vlieger, Jan 24 2016 *)
  • PARI
    is(n,b=9,c=10)=issquare(subst(Pol(digits(n,b)),x,c))
    
  • Python
    A267769_list = [int(s, 9) for s in (str(i**2) for i in range(10**6)) if max(s) < '9'] # Chai Wah Wu, Jan 20 2016

A267764 Numbers whose base-4 representation is a square when read in base 10.

Original entry on oeis.org

0, 1, 16, 25, 256, 289, 400, 441, 673, 1761, 1849, 4096, 4225, 4624, 4761, 6400, 6561, 7056, 7713, 10768, 13401, 28176, 29584, 65536, 66049, 67600, 68121, 73984, 74529, 76176, 76729, 77985, 102400, 103041, 104976, 112896, 113569, 123408, 150081, 172288, 214416, 450816, 473344, 501433, 519873
Offset: 1

Views

Author

M. F. Hasler, Jan 20 2016

Keywords

Comments

Trivially includes powers of 16, since 16^k = 100..00_4 = 10^(2k) when read as a base-10 number. Moreover, for any a(n) in the sequence, 16*a(n) is also in the sequence. One could call "primitive" the terms not of this form, these would be 1, 25 = 121_4, 289 = 10201_4, 441 = 12321_4, 673 = 22201_4, 1761 = 123201_4, ... These primitive terms include the subsequence 16^k + 2*4^k + 1 = (4^k+1)^2, k > 0, which yields A033934 when written in base 4.

Crossrefs

Cf. A267763 - A267769 for bases 3 through 9. The base-2 analog is A000302 = powers of 4.

Programs

  • Mathematica
    Select[Range[1000], IntegerQ[Sqrt[FromDigits[IntegerDigits[#, 4]]]] &] (* Alonso del Arte, Jan 23 2016 *)
  • PARI
    is(n,b=4,c=10)=issquare(subst(Pol(digits(n,b)),x,c))
    
  • Python
    A267764_list = [int(d,4) for d in (str(i**2) for i in range(10**6)) if max(d) < '4'] # Chai Wah Wu, Feb 23 2016

A267768 Numbers whose base-8 representation is a square when read in base 10.

Original entry on oeis.org

0, 1, 4, 14, 21, 30, 52, 64, 81, 100, 149, 174, 212, 241, 256, 289, 382, 405, 446, 532, 622, 661, 804, 849, 896, 1012, 1045, 1102, 1220, 1281, 1344, 1409, 1476, 1557, 1630, 1780, 1920, 2001, 2197, 2286, 2452, 2545, 2593, 2878, 2965, 3070, 3233, 3328, 3441, 3540, 3630, 3733, 4068, 4096
Offset: 1

Views

Author

M. F. Hasler, Jan 20 2016

Keywords

Comments

Trivially includes powers of 64, since 64^k = 100..00_8 = 10^(2k) when read in base 10. Moreover, for any a(n) in the sequence, 64*a(n) is also in the sequence. One could call "primitive" the terms not of this form. These primitive terms include the subsequence 64^k + 2*8^k + 1 = (8^k+1)^2, k > 0, which yields A033934 when written in base 8.
Motivated by the subsequence A267490 which lists the primes in this sequence.

Crossrefs

Cf. A267763 - A267769 for bases 3 through 9. The base-2 analog is A000302 = powers of 4.

Programs

  • Magma
    [n: n in [0..10^4] | IsSquare(Seqint(Intseq(n, 8)))]; // Vincenzo Librandi, Dec 28 2016
  • Mathematica
    Select[Range[0, 2 10^4], IntegerQ@Sqrt@FromDigits@IntegerDigits[#, 8] &] (* Vincenzo Librandi, Dec 28 2016 *)
  • PARI
    is(n,b=8,c=10)=issquare(subst(Pol(digits(n,b)),x,c))
    
  • Python
    A267768_list = [int(s, 8) for s in (str(i**2) for i in range(10**6)) if max(s) < '8'] # Chai Wah Wu, Jan 20 2016
    

A267765 Numbers whose base-5 representation is a square when read in base 10.

Original entry on oeis.org

0, 1, 4, 25, 36, 49, 89, 100, 121, 139, 249, 329, 351, 625, 676, 729, 900, 961, 1225, 1551, 1654, 2146, 2225, 2289, 2500, 2601, 3025, 3289, 3475, 3521, 3814, 4324, 4529, 4801, 5086, 5149, 6225, 6726, 6829, 7374, 8225, 8464, 8775, 9454, 9601, 13926, 15625, 15876, 16129, 16900, 17161
Offset: 1

Views

Author

M. F. Hasler, Jan 20 2016

Keywords

Comments

Trivially includes powers of 25, since 25^k = 100..00_5 = 10^(2k) when read in base 10. Moreover, for any a(n) in the sequence, 25*a(n) is also in the sequence. One could call "primitive" the terms not of this form, these would be 1, 4, 36 = 121_5, 49 = 144_5, 89 = 324_5, ... These primitive terms include the subsequence 25^k + 2*5^k + 1 = (5^k+1)^2, k > 0, which yields A033934 when written in base 5.

Crossrefs

Cf. A267763 - A267769 for bases 3 through 9. The base-2 analog is A000302 = powers of 4.

Programs

  • Mathematica
    Select[Range[0, 17200], IntegerQ@ Sqrt@ FromDigits@ IntegerDigits[#, 5] &] (* Michael De Vlieger, Jan 24 2016 *)
  • PARI
    is(n,b=5,c=10)=issquare(subst(Pol(digits(n,b)),x,c))
    
  • Python
    A267765_list = [int(d,5) for d in (str(i**2) for i in range(10**6)) if max(d) < '5'] # Chai Wah Wu, Mar 12 2016

A267766 Numbers whose base-6 representation is a square when read in base 10.

Original entry on oeis.org

0, 1, 4, 17, 36, 49, 64, 89, 124, 144, 169, 232, 305, 388, 409, 449, 544, 577, 612, 665, 953, 1105, 1296, 1369, 1444, 1529, 1764, 1849, 1936, 2033, 2304, 2825, 3097, 3204, 3280, 3473, 4345, 4464, 4588, 4841, 5104, 5184, 5329, 5633, 6084, 6241, 7081, 7649, 8044, 8352, 8449, 9160, 9593
Offset: 1

Views

Author

M. F. Hasler, Jan 20 2016

Keywords

Comments

Trivially includes powers of 36, since 36^k = 100..00_6 = 10^(2k) when read in base 10. Moreover, for any a(n) in the sequence, 36*a(n) is also in the sequence. One could call "primitive" the terms not of this form. These primitive terms include the subsequence 36^k + 2*6^k + 1 = (6^k+1)^2, k > 0, which yields A033934 when written in base 6.

Crossrefs

Cf. A267763 - A267769 for bases 3 through 9. The base-2 analog is A000302 = powers of 4.

Programs

  • Magma
    [n: n in [0..10^4] | IsSquare(Seqint(Intseq(n,6)))]; // Bruno Berselli, Jan 20 2016
    
  • Mathematica
    Select[Range[0, 10^4], IntegerQ@ Sqrt@ FromDigits@ IntegerDigits[#, 6] &] (* Michael De Vlieger, Jan 24 2016 *)
  • PARI
    is(n,b=6,c=10)=issquare(subst(Pol(digits(n,b)),x,c))
    
  • Python
    A267766_list = [int(d,6) for d in (str(i**2) for i in range(10**6)) if max(d) < '6'] # Chai Wah Wu, Mar 12 2016

A267767 Numbers whose base-7 representation is a square when read in base 10.

Original entry on oeis.org

0, 1, 4, 13, 19, 27, 46, 49, 64, 81, 117, 139, 165, 190, 196, 225, 313, 361, 433, 460, 571, 603, 637, 705, 748, 837, 883, 931, 981, 1048, 1105, 1222, 1323, 1489, 1560, 1684, 1744, 2028, 2185, 2254, 2346, 2401, 2500, 2601, 2763, 2869, 3084, 3136, 3249, 3364, 3547, 3667, 3865, 3969, 4096
Offset: 1

Views

Author

M. F. Hasler, Jan 20 2016

Keywords

Comments

Trivially includes powers of 49, since 49^k = 100..00_7 = 10^(2k) when read in base 10. Moreover, for any a(n) in the sequence, 49*a(n) is also in the sequence. One could call "primitive" the terms not of this form. These primitive terms include the subsequence 49^k + 2*7^k + 1 = (7^k+1)^2, k > 0, which yields A033934 when written in base 7.

Crossrefs

Cf. A267763 - A267769 for bases 3 through 9. The base-2 analog is A000302 = powers of 4.

Programs

  • Magma
    [n: n in [0..10^4] | IsSquare(Seqint(Intseq(n, 7)))]; // Vincenzo Librandi, Dec 28 2016
  • Mathematica
    Select[Range[0, 2 10^4], IntegerQ@Sqrt@FromDigits@IntegerDigits[#, 7] &] (* Vincenzo Librandi, Dec 28 2016 *)
  • PARI
    is(n,b=7,c=10)=issquare(subst(Pol(digits(n,b)),x,c))
    
  • Python
    A267767_list = [int(s, 7) for s in (str(i**2) for i in range(10**6)) if max(s) < '7'] # Chai Wah Wu, Jan 20 2016
    
Showing 1-6 of 6 results.