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 1-5 of 5 results.

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))

A048369 a(n)^3 is smallest cube containing exactly n 4's.

Original entry on oeis.org

4, 14, 114, 164, 763, 3543, 17066, 13464, 163974, 757364, 3421244, 6727219, 28902604, 35685649, 761777604, 1350780517, 2543012249, 7633715304, 101476238101, 163186746514, 353823251814, 5708006133707
Offset: 1

Views

Author

Patrick De Geest, Mar 15 1999

Keywords

Crossrefs

Programs

  • Mathematica
    nsmall = Table[Infinity, 15];
    For[i = 0, i <= 10^6, i++, n0 = Count[IntegerDigits[i^3], 4];
      If[nsmall[[n0]] > i, nsmall[[n0]] = i]];
    Cases[nsmall, ?NumberQ] (* _Robert Price, Mar 20 2020 *)

Extensions

a(15)-a(20) from Lars Blomberg, Jun 12 2011
a(21) from Giovanni Resta, Jun 29 2018
a(22) from Giovanni Resta, Mar 23 2020

A036528 Smallest cube containing exactly n 1's.

Original entry on oeis.org

0, 1, 1331, 195112, 1191016, 302111711, 1128111921, 1017501115112, 11540111711192, 3110921146111141, 111121611171697125, 13131411119181123391, 1091919111651131183181, 113111518118141111752, 1011911111044153611072111, 101151130119180103111112613
Offset: 0

Views

Author

Keywords

Comments

a(n)^(1/3) = A048366(n) is the index of the first occurrence of n in sequence A269241. - M. F. Hasler, Feb 21 2016

Crossrefs

Programs

  • Mathematica
    nsmall = Table[Infinity, 20];
    For[i = 0, i <= 10^6, i++, n0 = Count[IntegerDigits[i^3], 1];
      If[nsmall[[n0 + 1]] > i^3, nsmall[[n0 + 1]] = i^3]];
    Cases[nsmall, ?NumberQ] (* _Robert Price, Mar 20 2020 *)

Formula

a(n) = A048366(n)^3. - M. F. Hasler, Feb 21 2016

Extensions

a(12)-a(15) from Giovanni Resta, Jun 29 2018

A036529 Smallest cube containing exactly n 2's.

Original entry on oeis.org

0, 27, 21952, 2628072, 202262003, 229220928, 22521332224, 21148222722264, 25942222239227, 2272271222935232, 2262268226562252992, 4223937222222326272, 22225347273222227224, 122245292222422449622424, 2732072222242422541222208, 22422524292920620222272827
Offset: 0

Views

Author

Keywords

Comments

a(n)^(1/3) = A048367(n) is the index of the first occurrence of n in sequence A269242. - M. F. Hasler, Feb 21 2016

Crossrefs

Programs

  • Mathematica
    nsmall = Table[Infinity, 20];
    For[i = 0, i <= 10^6, i++, n0 = Count[IntegerDigits[i^3], 2];
      If[nsmall[[n0 + 1]] > i^3, nsmall[[n0 + 1]] = i^3]];
    Cases[nsmall, ?NumberQ] (* _Robert Price, Mar 20 2020 *)

Formula

a(n) = A048367(n)^3. - M. F. Hasler, Feb 21 2016

Extensions

a(12)-a(15) from Giovanni Resta, Jun 29 2018

A036530 Smallest cube containing exactly n 3's.

Original entry on oeis.org

0, 4913, 343, 5735339, 108531333, 353393243, 333533450375, 3707322336333, 86333306433373, 153712433903333733, 333343033492332032, 8343304933332333329, 433134325352337333353, 33435346723033333302433, 243513939323833732333333, 33393753313938361233336383
Offset: 0

Views

Author

Keywords

Comments

a(n)^(1/3) = A048368(n) is the index of the first occurrence of n in sequence A269243. - M. F. Hasler, Feb 21 2016

Crossrefs

Programs

  • Mathematica
    Table[SelectFirst[Range[2100000]^3,DigitCount[#,10,3]==n&],{n,11}] (* The program uses the SelectFirst function from Mathematica version 10 *) (* Harvey P. Dale, Oct 24 2015 *)

Formula

a(n) = A048368(n)^3. - M. F. Hasler, Feb 21 2016

Extensions

a(0) = 0 prefixed by M. F. Hasler, Feb 21 2016
a(12)-a(15) from Giovanni Resta, Jun 29 2018
Showing 1-5 of 5 results.