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.

Previous Showing 11-20 of 22 results. Next

A195943 Zeroless prime powers: Intersection of A000961 and A052382.

Original entry on oeis.org

1, 2, 3, 4, 5, 7, 8, 9, 11, 13, 16, 17, 19, 23, 25, 27, 29, 31, 32, 37, 41, 43, 47, 49, 53, 59, 61, 64, 67, 71, 73, 79, 81, 83, 89, 97, 113, 121, 125, 127, 128, 131, 137, 139, 149, 151, 157, 163, 167, 169, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 243, 251, 256, 257, 263, 269, 271, 277, 281, 283, 289, 293, 311
Offset: 1

Views

Author

M. F. Hasler, Sep 25 2011

Keywords

Comments

In contrast to A195942, we also allow for primes (p^n with n=1) in this sequence.

Crossrefs

Programs

  • Haskell
    a195943 n = a195943_list !! (n-1)
    a195943_list = filter ((== 1) . a010055) a052382_list
    -- Reinhard Zumkeller, Sep 27 2011
  • PARI
    for( n=1,9999, is_A000961(n) && is_A052382(n) && print1(n","))
    

Formula

A010055(a(n)) * A168046(a(n)) = 1. - Reinhard Zumkeller, Sep 27 2011

A195942 Zeroless prime powers (excluding primes): Intersection of A025475 and A052382.

Original entry on oeis.org

1, 4, 8, 9, 16, 25, 27, 32, 49, 64, 81, 121, 125, 128, 169, 243, 256, 289, 343, 361, 512, 529, 625, 729, 841, 961, 1331, 1369, 1681, 1849, 2187, 2197, 3125, 3481, 3721, 4489, 4913, 5329, 6241, 6561, 6859, 6889, 7921, 8192
Offset: 1

Views

Author

M. F. Hasler, Sep 25 2011

Keywords

Crossrefs

Programs

  • Haskell
    a195942 n = a195942_list !! (n-1)
    a195942_list = filter (\x -> a010051 x == 0 && a010055 x == 1) a052382_list
    -- Reinhard Zumkeller, Sep 27 2011
  • Mathematica
    mx = 10^10; t = {1}; p = 2; While[pw = 2; While[n = p^pw; n <= mx, If[Union[IntegerDigits[n]][[1]] > 0, AppendTo[t, n]]; pw++]; pw > 2, p = NextPrime[p]]; t = Sort[t] (* T. D. Noe, Sep 27 2011 *)
  • PARI
    for( n=1,9999, is_A025475(n) && is_A052382(n) && print1(n","))
    

Formula

A195942 = A025475 intersect A052382.
A010055(a(n)) * (1 - A010051(a(n))) * A168046(a(n)) = 1. - Reinhard Zumkeller, Sep 27 2011

A195944 Numbers k such that 13^k has no zero in its decimal expansion.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 7, 10, 14
Offset: 1

Views

Author

M. F. Hasler, Sep 25 2011

Keywords

Comments

Probably finite. Is 14 the largest term?

Crossrefs

Programs

  • Magma
    [n: n in [0..1000] | not 0 in Intseq(13^n) ]; // Vincenzo Librandi, May 06 2015
  • Mathematica
    Select[Range[0,20],DigitCount[13^#,10,0]==0&] (* Harvey P. Dale, May 24 2023 *)
  • PARI
    for( n=0,9999, is_A052382(13^n) && print1(n","))
    

Formula

Equals { n | A001022(n) is in A052382 }.

Extensions

Keyword:fini removed by Jianing Song, Jan 28 2023 as finiteness is only conjectured.

A195948 Powers of 5 which have no zero in their decimal expansion.

Original entry on oeis.org

1, 5, 25, 125, 625, 3125, 15625, 78125, 1953125, 9765625, 48828125, 762939453125, 3814697265625, 931322574615478515625, 116415321826934814453125, 34694469519536141888238489627838134765625
Offset: 1

Views

Author

M. F. Hasler, Sep 25 2011

Keywords

Comments

Probably finite. Is 34694469519536141888238489627838134765625 the largest term?

Crossrefs

Programs

  • Mathematica
    Select[5^Range[0,60],DigitCount[#,10,0]==0&] (* Harvey P. Dale, Aug 30 2016 *)
  • PARI
    for( n=0,9999, is_A052382(5^n) && print1(5^n,","))

Formula

a(n) = 5^A008839(n).
A000351 intersect A052382.

Extensions

Keyword:fini removed by Jianing Song, Jan 28 2023 as finiteness is only conjectured.

A238938 Powers of 2 without the digit '0' in their decimal expansion.

Original entry on oeis.org

1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 8192, 16384, 32768, 65536, 262144, 524288, 16777216, 33554432, 134217728, 268435456, 2147483648, 4294967296, 8589934592, 17179869184, 34359738368, 68719476736, 137438953472, 549755813888, 562949953421312, 2251799813685248, 147573952589676412928
Offset: 1

Views

Author

M. F. Hasler, Mar 07 2014

Keywords

Comments

Conjectured to be finite and complete. See the OEIS wiki page for further information, references and links.

Examples

			256 = 2^8 is in the sequence because 256 has a 2, a 5 and a 6 but no 0's.
512 = 2^9 is also in because it has a 1, a 2 and a 5 but no 0's.
1024 = 2^10 is not in the sequence because it has a 0.
		

Crossrefs

Programs

  • Mathematica
    Select[2^Range[0, 127], DigitCount[#, 10, 0] == 0 &] (* Alonso del Arte, Mar 07 2014 *)
  • PARI
    for(n=0,99,vecmin(digits(2^n))&& print1(2^n","))

Formula

a(n) = 2^A007377(n).

Extensions

'fini' keyword removed as finiteness is only conjectured by Max Alekseyev, Apr 10 2019

A238939 Powers of 3 without the digit '0' in their decimal expansion.

Original entry on oeis.org

1, 3, 9, 27, 81, 243, 729, 2187, 6561, 19683, 177147, 531441, 1594323, 4782969, 1162261467, 94143178827, 282429536481, 2541865828329, 7625597484987, 22876792454961, 617673396283947, 16677181699666569, 278128389443693511257285776231761
Offset: 1

Views

Author

M. F. Hasler, Mar 07 2014

Keywords

Comments

Conjectured to be finite and complete. See the OEIS wiki page for further information, references and links.

Crossrefs

For the zeroless numbers (powers x^n), see A238938, A238939, A238940, A195948, A238936, A195908, A195946, A195945, A195942, A195943, A103662.
For the corresponding exponents, see A007377, A008839, A030700, A030701, A008839, A030702, A030703, A030704, A030705, A030706, A195944.
For other related sequences, see A052382, A027870, A102483, A103663.

Programs

  • Mathematica
    Select[3^Range[0,100],DigitCount[#,10,0]==0&] (* Paolo Xausa, Oct 07 2023 *)
  • PARI
    for(n=0,99,vecmin(digits(3^n))&& print1(3^n","))

Formula

a(n) = 3^A030700(n).

Extensions

Keyword:fini removed by Jianing Song, Jan 28 2023 as finiteness is only conjectured.

A238936 Powers of 6 without the digit '0' in their decimal expansion.

Original entry on oeis.org

1, 6, 36, 216, 1296, 7776, 46656, 279936, 1679616, 2176782336, 16926659444736, 4738381338321616896, 36845653286788892983296, 17324272922341479351919144385642496
Offset: 1

Views

Author

M. F. Hasler, Mar 07 2014

Keywords

Comments

Conjectured to be finite and complete. See the OEIS wiki page for further information, references and links.

Crossrefs

Programs

  • Mathematica
    Select[6^Range[0,50],DigitCount[#,10,0]==0&] (* Harvey P. Dale, Dec 03 2020 *)
  • PARI
    for(n=0,99,vecmin(digits(6^n))&& print1(6^n","))

Formula

a(n)=6^A030702(n).

Extensions

Keyword:fini and keyword:full removed by Jianing Song, Jan 28 2023 as finiteness is only conjectured.

A238940 Powers of 4 without the digit '0' in their decimal expansion.

Original entry on oeis.org

1, 4, 16, 64, 256, 16384, 65536, 262144, 16777216, 268435456, 4294967296, 17179869184, 68719476736, 4722366482869645213696, 75557863725914323419136, 77371252455336267181195264
Offset: 1

Views

Author

M. F. Hasler, Mar 07 2014

Keywords

Comments

Conjectured to be finite and complete. See the OEIS wiki page for further information, references and links.

Crossrefs

For the zeroless numbers (powers x^n), see A238938, A238939, A238940, A195948, A238936, A195908, A195946, A195945, A195942, A195943.
For the corresponding exponents, see A007377, A008839, A030700, A030701, A030702, A030703, A030704, A030705, A030706, A195944.
For other related sequences, see A052382, A027870, A102483.

Programs

  • Mathematica
    Select[4^Range[0,50],DigitCount[#,10,0]==0&] (* Harvey P. Dale, Aug 31 2021 *)
  • PARI
    for(n=0,99,vecmin(digits(4^n))&& print1(4^n","))

Formula

a(n)=4^A030701(n).

Extensions

Keyword:fini removed by Jianing Song, Jan 28 2023 as finiteness is only conjectured.

A305939 Number of powers of 9 having exactly n digits '0' (in base 10), conjectured.

Original entry on oeis.org

12, 7, 18, 3, 9, 13, 11, 11, 6, 9, 17, 15, 12, 9, 11, 6, 9, 9, 9, 13, 16, 9, 10, 7, 7, 9, 9, 13, 14, 15, 14, 15, 9, 9, 8, 8, 15, 11, 11, 12, 5, 12, 14, 5, 7, 14, 10, 8, 5, 16, 12
Offset: 0

Views

Author

M. F. Hasler, Jun 22 2018

Keywords

Comments

a(0) = 12 is the number of terms in A030705 and in A195945, which includes the power 7^0 = 1.
These are the row lengths of A305929. It remains an open problem to provide a proof that these rows are complete (as for all terms of A020665), but the search has been pushed to many orders of magnitude beyond the largest known term, and the probability of finding an additional term is vanishing, cf. Khovanova link.

Crossrefs

Cf. A030705 = row 0 of A305929: k such that 9^k has no 0's; A195945: these powers 9^k.
Cf. A020665: largest k such that n^k has no '0's.
Cf. A063626 = column 1 of A305929: least k such that 9^k has n digits 0 in base 10.
Cf. A305942 (analog for 2^k), ..., A305947, A305938 (analog for 8^k).

Programs

  • PARI
    A305939(n,M=99*n+199,x=9)=sum(k=0,M,#select(d->!d,digits(x^k))==n)
    
  • PARI
    A305939_vec(nMax,M=99*nMax+199,x=9,a=vector(nMax+=2))={for(k=0,M,a[min(1+#select(d->!d,digits(x^k)),nMax)]++);a[^-1]}

A245853 Powers of 12 without the digit '0' in their decimal expansion.

Original entry on oeis.org

1, 12, 144, 1728, 248832, 2985984, 429981696, 61917364224, 1283918464548864, 3833759992447475122176, 11447545997288281555215581184
Offset: 1

Views

Author

Vincenzo Librandi, Aug 04 2014

Keywords

Comments

Conjectured to be finite.

Crossrefs

Cf. Powers of k without the digit '0' in their decimal expansion: A238938 (k=2), A238939 (k=3), A238940 (k=4), A195948 (k=5), A238936 (k=6), A195908 (k=7), A245852 (k=8), A240945 (k=9), A195946 (k=11), this sequence (k=12), A195945 (k=13).

Programs

  • Magma
    [12^n: n in [0..3*10^4] | not 0 in Intseq(12^n)];
  • Mathematica
    Select[12^Range[0, 2*10^5], DigitCount[#, 10, 0]==0 &]
Previous Showing 11-20 of 22 results. Next