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 29 results. Next

A037069 Smallest prime containing exactly n 8's.

Original entry on oeis.org

2, 83, 881, 8887, 88883, 888887, 28888883, 88888883, 888888883, 48888888883, 288888888889, 888888888887, 48888888888883, 88888888888889, 888888888888883, 18888888888888883, 88888888888888889, 2888888888888888887, 8888888888888888881, 388888888888888888889
Offset: 0

Views

Author

Patrick De Geest, Jan 04 1999

Keywords

Comments

The last digit of n cannot be 8, therefore a(n) must have at least n+1 digits. It is probable (using [] for floor) that none among [10^n/9]*80 + {1,3,7,9} is prime in which case a(n) must have n+2 digits. We conjecture that for all n >= 0, a(n) equals [10^(n+1)/9]*80 + b with 1 <= b <= 9 and one of the (first) digits 8 replaced by a digit among {0, ..., 7}. - M. F. Hasler, Feb 22 2016

Crossrefs

Programs

  • Mathematica
    f[n_, b_] := Block[{k = 10^(n + 1), p = Permutations[ Join[ Table[b, {i, 1, n}], {x}]], c = Complement[Table[j, {j, 0, 9}], {b}], q = {}}, Do[q = Append[q, Replace[p, x -> c[[i]], 2]], {i, 1, 9}]; r = Min[ Select[ FromDigits /@ Flatten[q, 1], PrimeQ[ # ] & ]]; If[r ? Infinity, r, p = Permutations[ Join[ Table[ b, {i, 1, n}], {x, y}]]; q = {}; Do[q = Append[q, Replace[p, {x -> c[[i]], y -> c[[j]]}, 2]], {i, 1, 9}, {j, 1, 9}]; Min[ Select[ FromDigits /@ Flatten[q, 1], PrimeQ[ # ] & ]]]]; Table[ f[n, 8], {n, 1, 18}]
  • PARI
    A037069(n)={my(p, t=10^(n+1)\9*80); forvec(v=[[-1, n], [-8, -1]], nextprime(p=t+10^(n-v[1])*v[2])-p<10 && return(nextprime(p)))} \\ ~

Formula

a(n) = prime(A037068(n)). - Amiram Eldar, Jul 21 2025

Extensions

Corrected by Jud McCranie, Jan 04 2001
More terms from Erich Friedman, Jun 03 2001
More terms and a(0) = 2 from M. F. Hasler, Feb 22 2016

A269250 Number of times the digit 0 appears in the decimal expansion of n^3.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 1, 0, 0, 0, 3, 0, 1, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 1, 0, 0, 1, 0, 0, 3, 0, 1, 1, 0, 0, 0, 1, 1, 0, 3, 0, 2, 0, 0, 0, 0, 0, 0, 1, 3, 0, 0, 2, 0, 0, 0, 2, 0, 1, 3, 0, 0, 1, 1, 0, 0, 0, 0, 1, 3, 0, 0, 0, 1, 0, 1, 1, 0, 1, 3, 0, 0, 1, 1, 0, 0, 0, 0, 1, 6
Offset: 0

Views

Author

M. F. Hasler, Feb 20 2016

Keywords

Comments

The cubes corresponding to the first occurrence of 1, 2, 3, ... are listed in A036527, i.e., A048365(n) = A036527(n)^(1/3) is the index of the first occurrence of n.

Examples

			1^3 = 1, 2^3 = 8, 3^3 = 27, 4^3 = 64, ..., 9^3 = 729 all have a(1) = a(2) = ... = a(9) = 0 digits '0'.
0^3 = 0 has a(0) = 1 digit '0'.
10^3 = 1000 has a(10) = 3 digits '0'.
		

Crossrefs

Analog for the other digits 1, ..., 9: A269241, A269242, A269243, A269244, A269245, A269246, A269247, A269248, A269249.
Analog for squares: A086008 (digit 0), and A086009 - A086017 for digits 1 - 9.

Programs

  • Maple
    seq(numboccur(0, convert(n^3,base,10)), n=0..100); # Robert Israel, Feb 21 2016
  • Mathematica
    Table[DigitCount[n^3, 10, 0], {n, 0, 100}] (* Robert Price, Mar 21 2020 *)
  • PARI
    A269250(n)=!n+#select(t->!t,digits(n^3))

A269241 Number of times the digit 1 appears in the decimal expansion of n^3.

Original entry on oeis.org

0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 1, 2, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 2, 1, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 2, 0, 1, 2, 2, 1, 2, 1, 1, 1, 1, 2, 2, 3, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 2, 0, 1, 0, 1, 0, 0, 0, 0, 1, 2, 1, 1, 0, 2, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0
Offset: 0

Views

Author

M. F. Hasler, Feb 20 2016

Keywords

Comments

The cubes corresponding to the first occurrence of 1, 2, 3, ... are listed in A036528, i.e., A036528(n)^(1/3) = A048366(n) is the index of the first occurrence of n.

Examples

			0^3 = 0 has a(0) = 0 digits '1'.
1^3 = 1 has a(1) = 1 digit '1'.
2^3 = 8 has a(2) = 0 digits '1'.
3^3 = 27 has a(3) = 0 digits '1'.
4^3 = 64 has a(4) = 0 digits '1'.
5^3 = 125 has a(5) = 1 digit '1'.
11^3 = 1331 is the smallest cube to have a(11) = 2 digits '1'.
		

Crossrefs

Analog for the other digits 0, 2, ..., 9: A269250, A269242, A269243, A269244, A269245, A269246, A269247, A269248, A269249.
Analog for squares: A086009 (digit 1), and A086008 - A086017 for digits 0 - 9.

Programs

  • Mathematica
    Table[DigitCount[n^3, 10, 1], {n, 0, 99}] (* Alonso del Arte, Feb 20 2016 *)
  • PARI
    A269241(n)=#select(t->t==1,digits(n^3))

A269242 Number of times the digit 2 appears in the decimal expansion of n^3.

Original entry on oeis.org

0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 2, 1, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 2, 2, 1, 2, 2, 1, 0, 1, 1, 0, 0, 1, 0, 2, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1
Offset: 0

Views

Author

M. F. Hasler, Feb 20 2016

Keywords

Comments

The cubes corresponding to the first occurrence of 1, 2, 3, ... are listed in A036529, i.e., A036529(n)^(1/3) = A048367(n) is the index of the first occurrence of n.

Examples

			0^3 = 0 has a(0) = 0 digits '2'.
1^3 = 1 has a(1) = 0 digits '2'.
2^3 = 8 has a(2) = 0 digits '2'.
3^3 = 27 has a(3) = 1 digits '2'.
4^3 = 64 has a(4) = 0 digits '2'.
5^3 = 125 has a(5) = 1 digit '2'.
28^3 = 21952 is the least cube which has a(28) = 2 digits '2'.
		

Crossrefs

Analog for the other digits 0, 1, ..., 9: A269250, A269241, A269242, A269243, A269244, A269245, A269246, A269247, A269248, A269249.
Analog for squares: A086010 (digit 2), and A086008 - A086017 for digits 0 - 9.

Programs

  • Magma
    [Multiplicity(Intseq(n^3),2): n in [0..100]]; // Marius A. Burtea, Jan 26 2020
  • Maple
    seq(numboccur(2,convert(n^3,base,10)),n=0..100); # Robert Israel, Jan 26 2020
  • Mathematica
    Table[DigitCount[n^3, 10, 2], {n, 0, 100}] (* Robert Price, Mar 21 2020 *)
  • PARI
    A269242(n)=#select(t->t==2,digits(n^3))
    

A269243 Number of times the digit 3 appears in the decimal expansion of n^3.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 2, 0, 0, 0, 2, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 2, 2, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 2, 2, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 2, 0, 0, 0, 0, 2, 2, 1, 2, 1, 2, 1, 0, 0, 1, 2, 0, 2, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1
Offset: 0

Views

Author

M. F. Hasler, Feb 20 2016

Keywords

Comments

The cubes corresponding to the first occurrence of 1, 2, 3, ... are listed in A036530, i.e., A036530(n)^(1/3) = A048368(n) is the index of the first occurrence of n.

Examples

			0^3 = 0, 1^3 = 1, 2^3 = 8, 3^3 = 27, 4^3 = 64, 5^3 = 125 and 6^3 = 216 all have a(0) = a(1) = ... = a(6) = 0 digits '3'.
7^3 = 343 has a(7) = 2 digits '3'.
		

Crossrefs

Analog for the other digits 0, 1, ..., 9: A269250, A269241, A269242, A269243, A269244, A269245, A269246, A269247, A269248, A269249.
Analog for squares: A086011 (digit 3), and A086008 - A086017 for digits 0 - 9.

Programs

  • Mathematica
    Table[DigitCount[n^3, 10, 3], {n, 0, 100}] (* Robert Price, Mar 21 2020 *)
  • PARI
    A269243(n)=#select(t->t==3,digits(n^3))

A269244 Number of times the digit 4 appears in the decimal expansion of n^3.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 2, 0, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 1, 1, 0, 2, 0, 1, 0, 1, 0, 2, 1, 1, 1, 2, 1, 0, 2, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1
Offset: 0

Views

Author

M. F. Hasler, Feb 20 2016

Keywords

Comments

The cubes corresponding to the first occurrence of 1, 2, 3, ... are listed in A036531, i.e., A036531(n)^(1/3) = A048369(n) is the index of the first occurrence of n.

Examples

			0^3 = 0, 1^3 = 1, 2^3 = 8 and 3^3 = 27 all have a(0) = a(1) = a(2) = a(3) = 0 digits '4'.
4^3 = 64 has a(4) = 1 digit '4'.
14^3 = 2744 has a(14) = 2 digits '4'.
		

Crossrefs

Analog for the other digits 0, 1, ..., 9: A269250, A269241, A269242, A269243, A269244, A269245, A269246, A269247, A269248, A269249.
Analog for squares: A086012 (digit 4), and A086008 - A086017 for digits 0 - 9.

Programs

  • Mathematica
    Table[DigitCount[n^3, 10, 4], {n, 0, 100}] (* Robert Price, Mar 21 2020 *)
  • PARI
    A269244(n)=#select(t->t==4,digits(n^3))

A269245 Number of times the digit 5 appears in the decimal expansion of n^3.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 2, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 1, 2, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 2, 2, 0, 1, 1, 2, 1, 1, 1, 1, 2, 0, 0, 0, 2, 0, 1, 1, 2
Offset: 0

Views

Author

M. F. Hasler, Feb 20 2016

Keywords

Comments

The cubes corresponding to the first occurrence of 1, 2, 3, ... are listed in A036532, i.e., A036532(n)^(1/3) = A048370(n) is the index of the first occurrence of n.

Examples

			0^3 = 0, 1^3 = 1, 2^3 = 8 and 3^3 = 27 all have a(0) = a(1) = a(2) = a(3) = 0 digits '5'.
5^3 = 125 has a(5) = 1 digit '5'.
		

Crossrefs

Analog for the other digits 0, 1, ..., 9: A269250, A269241, A269242, A269243, A269244, A269245, A269246, A269247, A269248, A269249.
Analog for squares: A086013 (digit 5), and A086008 - A086017 for digits 0 - 9.

Programs

  • Mathematica
    Table[DigitCount[n^3, 10, 5], {n, 0, 100}] (* Robert Price, Mar 21 2020 *)
  • PARI
    A269245(n)=#select(t->t==5,digits(n^3))

A269246 Number of times the digit 6 appears in the decimal expansion of n^3.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 3, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 2, 2, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 3, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0
Offset: 0

Views

Author

M. F. Hasler, Feb 20 2016

Keywords

Comments

The cubes corresponding to the first occurrence of 1, 2, 3, ... are listed in A036533, i.e., A036533(n)^(1/3) = A048371(n) is the index of the first occurrence of n.

Examples

			0^3 = 0, 1^3 = 1, 2^3 = 8 and 3^3 = 27 all have a(0) = a(1) = a(2) = a(3) = 0 digits '6'.
4^3 = 64 has a(4) = 1 digit '6'.
		

Crossrefs

Analog for the other digits 0, 1, ..., 9: A269250, A269241, A269242, A269243, A269244, A269245, A269246, A269247, A269248, A269249.
Analog for squares: A086014 (digit 6), and A086008 - A086017 for digits 0 - 9.

Programs

  • Mathematica
    Table[DigitCount[n^3, 10, 6], {n, 0, 100}] (* Robert Price, Mar 21 2020 *)
  • PARI
    A269246(n)=#select(t->t==6,digits(n^3))

A269247 Number of times the digit 7 appears in the decimal expansion of n^3.

Original entry on oeis.org

0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 2, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 2, 0, 0, 1, 0, 0, 1, 0, 0, 0, 2, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 3, 1, 0, 0, 0, 1, 1, 1, 2, 2, 1, 0, 2, 1, 1, 0, 1, 0
Offset: 0

Views

Author

M. F. Hasler, Feb 20 2016

Keywords

Comments

The cubes corresponding to the first occurrence of 1, 2, 3, ... are listed in A036534, i.e., A036534(n)^(1/3) = A048372(n) is the index of the first occurrence of n.

Examples

			0^3 = 0, 1^3 = 1, 2^3 = 8 and 4^3 = 64 all have a(0) = a(1) = a(2) = a(4) = 0 digits '7'.
3^3 = 27 has a(3) = 1 digit '7'.
		

Crossrefs

Analog for the other digits 0, 1, ..., 9: A269250, A269241, A269242, A269243, A269244, A269245, A269246, A269247, A269248, A269249.
Analog for squares: A086015 (digit 7), and A086008 - A086017 for digits 0 - 9.

Programs

  • Mathematica
    Table[DigitCount[n^3, 10, 7], {n, 0, 100}] (* Robert Price, Mar 21 2020 *)
  • PARI
    A269247(n)=#select(t->t==7,digits(n^3))

A269248 Number of times the digit 8 appears in the decimal expansion of n^3.

Original entry on oeis.org

0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 2, 0, 2, 0, 0, 1, 0, 0, 0, 0, 1, 2, 0, 0, 0, 1, 0, 0, 0, 1, 2, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 3, 1, 2, 1, 2, 0, 0, 0, 0
Offset: 0

Views

Author

M. F. Hasler, Feb 20 2016

Keywords

Comments

The cubes corresponding to the first occurrence of 1, 2, 3, ... are listed in A036535, i.e., A036535(n)^(1/3) = A048373(n) is the index of the first occurrence of n.

Examples

			0^3 = 0, 1^3 = 1, 3^3 = 27 and 4^3 = 64 all have a(0) = a(1) = a(3) = a(4) = 0 digits '8'.
2^3 = 8 has a(2) = 1 digit '8'.
		

Crossrefs

Analog for other digits 0, 1, ..., 7, 9: A269250, A269241, A269242, A269243, A269244, A269245, A269246, A269247, A269249.
Analog for squares: A086016, and A086008 - A086017 for digits 0 - 9.

Programs

  • Mathematica
    Table[DigitCount[n^3, 10, 8], {n, 0, 100}] (* Robert Price, Mar 21 2020 *)
  • PARI
    A269248(n)=#select(t->t==8,digits(n^3))
Previous Showing 11-20 of 29 results. Next