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 1-8 of 8 results.

A061096 Let k = n-th number that is a possible digit-sum for a cube (A054966); sequence gives smallest cube with digit-sum k.

Original entry on oeis.org

1, 8, 27, 64, 2744, 729, 2197, 17576, 19683, 6859, 148877, 287496, 438976, 778688, 2299968, 3869893, 43986977, 75686967, 174676879, 596947688, 796597983, 1693669888, 9649992689, 56888939736, 7598896696, 78898389569, 197747699976, 677298787768, 1778597976896
Offset: 0

Views

Author

Amarnath Murthy, Apr 19 2001

Keywords

Examples

			a(5) = 2744, sum of digits = 17, the fifth term of A054966 (1,8,9,10,17,18...)
		

References

  • Amarnath Murthy, Fabricating a perfect cube with a given valid digit sum (to be published)

Crossrefs

Formula

a(n) = A067177(n)^3. - R. J. Mathar, Aug 23 2018

Extensions

More terms from Sascha Kurz, Jan 28 2003

A135043 Duplicate of A054966.

Original entry on oeis.org

0, 1, 8, 9, 10, 17, 18, 19, 26, 27, 28, 35, 36, 37, 44, 45, 46, 53, 54, 55, 62, 63, 64, 71, 72, 73, 80, 81, 82, 89, 90, 91, 98, 99, 100, 107, 108, 109, 116, 117, 118, 125, 126, 127, 134, 135, 136
Offset: 1

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Author

Keywords

Extensions

The b-file has been removed. - N. J. A. Sloane, Jan 19 2019

A016779 a(n) = (3*n + 1)^3.

Original entry on oeis.org

1, 64, 343, 1000, 2197, 4096, 6859, 10648, 15625, 21952, 29791, 39304, 50653, 64000, 79507, 97336, 117649, 140608, 166375, 195112, 226981, 262144, 300763, 343000, 389017, 438976, 493039, 551368, 614125, 681472, 753571, 830584, 912673, 1000000, 1092727, 1191016
Offset: 0

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Author

Keywords

Comments

The inverse binomial transform is 1, 63, 216, 162, 0, 0, 0 (0 continued). R. J. Mathar, May 07 2008
Perfect cubes with digital root 1 in base 10. Proof: perfect cubes are one of (3*s)^3, (3*s+1)^3 or (3*s+2)^3. Digital roots of (3*s)^3 are 0, digital roots of (3*s+1)^3 are 1, and digital roots of (3*s+2)^3 are 8, using trinomial expansion and the multiplicative property of digits roots. - R. J. Mathar, Jul 31 2010

Examples

			a(2) = (3*2+1)^3 = 343.
a(6) = (3*6+1)^3 = 6859.
		

References

  • S. R. Finch, Mathematical Constants, Cambridge, 2003, Section 1.6.3.
  • Amarnath Murthy, Fabricating a perfect cube with a given valid digit sum (to be published)

Crossrefs

Programs

Formula

Sum_{n>=0} 1/a(n) = 2*Pi^3 / (81*sqrt(3)) + 13*zeta(3)/27.
O.g.f.: (1 + 60*x + 93*x^2 + 8*x^3)/(1 - x)^4. - R. J. Mathar, May 07 2008
E.g.f.: (1 + 63*x + 108*x^2 + 27*x^3)*exp(x). - Ilya Gutkovskiy, Jun 16 2016
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). - Wesley Ivan Hurt, Oct 02 2020
Sum_{n>=1} (-1)^n/a(n) = A226735. - R. J. Mathar, Feb 07 2024

A016791 a(n) = (3*n + 2)^3.

Original entry on oeis.org

8, 125, 512, 1331, 2744, 4913, 8000, 12167, 17576, 24389, 32768, 42875, 54872, 68921, 85184, 103823, 125000, 148877, 175616, 205379, 238328, 274625, 314432, 357911, 405224, 456533, 512000, 571787, 636056, 704969, 778688, 857375, 941192, 1030301, 1124864, 1225043
Offset: 0

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Author

Keywords

Comments

Also the perfect cubes with digital root 8. [Proof: perfect cubes are either of the form (3n)^3 or of the form (3n+1)^3 or of the form (3n+2)^3. These subsets have digital root 9, 1 and 8 respectively.] - R. J. Mathar, Oct 02 2008

Examples

			a(4) = (3*4 + 2)^3 = 2744.
a(8) = (3*8 + 2)^3 = 17576.
		

References

  • Amarnath Murthy, Fabricating a perfect cube with a given valid digit sum (to be published)

Crossrefs

Programs

  • Mathematica
    (3*Range[0,40]+2)^3 (* or *) LinearRecurrence[{4,-6,4,-1},{8,125,512,1331},40] (* Harvey P. Dale, Feb 20 2013 *)
  • PARI
    a(n) = { (3*n + 2)^3 } \\ Harry J. Smith, Jul 18 2009

Formula

a(n) = A016789(n)^3. - Nathaniel Johnston, May 04 2011
G.f.: (8 + 93*x + 60*x^2 + x^3)/(1 - 4*x + 6*x^2 - 4*x^3 + x^4). - Colin Barker, Jan 02 2012
a(0)=8, a(1)=125, a(2)=512, a(3)=1331, a(n)=4*a(n-1)-6*a(n-2)+4*a(n-3)-a(n-4). - Harvey P. Dale, Feb 20 2013
Sum_{n>=0} 1/a(n) = -2*Pi^3 / (81*sqrt(3)) + 13*zeta(3)/27. - Amiram Eldar, Oct 02 2020

Extensions

More terms from Harry J. Smith, Jul 18 2009
First digital root in proof in comment line corrected. - Ant King, May 01 2013

A159462 Numbers n with property that sod(n^3) = 5^3.

Original entry on oeis.org

341075, 423299, 446423, 542657, 638144, 661529, 667163, 786599, 798899, 828113, 837719, 841733, 842921, 861683, 869513, 879353, 883595, 887813, 887819, 905882, 912176, 912299, 919676, 923144, 927926, 928259, 928298, 943538, 950216, 954635
Offset: 1

Views

Author

Zak Seidov, Apr 12 2009

Keywords

Comments

Numbers n with property that A007953(n^3) = 5^3.

Examples

			341075^3 = 39677989979796875, 3+9+6+7+7+9+8+9+9+7+9+7+9+6+8+7+5 = 125 = 5^3.
		

Crossrefs

Cf. A054966 Numbers that are congruent to {0, 1, 8} mod 9. A054966 Possible sums of digits of cubes. A067075 a(n) = smallest number m such that the sum of the digits of m^3 is equal to n^3. A007953 Digital sum (i.e. sum of digits) of n. A159463 Numbers n with property that sod(n^3) = 6^3.

Programs

  • Mathematica
    Select[Range[10^6],Total[IntegerDigits[#^3]]==125&] (* Harvey P. Dale, Jun 29 2022 *)
  • PARI
    isok(n) = sumdigits(n^3) == 125; \\ Michel Marcus, Oct 16 2013

A159463 Numbers n with property that sod(n^3) = 6^3.

Original entry on oeis.org

3848163483, 4462569999, 4479677412, 4586158119, 4594661259, 4594665192, 4594700889, 4625720379, 4641588459, 5644008999, 5828410842, 5833034823, 5838252576, 5848025709, 6453471192, 6617331999, 6619097067, 6686657169, 7107126942, 7230291999, 7277907183
Offset: 1

Views

Author

Zak Seidov, Apr 12 2009

Keywords

Comments

Numbers n with property that A007953(n^3) = 6^3.

Examples

			3848163483^3 = 56984998629886989599887999587, 5+6+9+8+4+9+9+8+6+2+9+8+8+6+9+8+9+5+9+9+8+8+7+9+9+9+5+8+7 = 216 = 6^3.
		

Crossrefs

Cf. A054966 Numbers that are congruent to {0, 1, 8} mod 9. A054966 Possible sums of digits of cubes. A067075 a(n) = smallest number m such that the sum of the digits of m^3 is equal to n^3. A007953 Digital sum (i.e., sum of digits) of n.
Numbers n such that sum of digits of n^3 is k^3: A107679 (k=2), A290842 (k=3), A290843 (k=4), A159462 (k=5), this sequence (k=6).

Extensions

a(16)-a(21) from Seiichi Manyama, Aug 12 2017

A067177 Cube root of A061096(n).

Original entry on oeis.org

1, 2, 3, 4, 14, 9, 13, 26, 27, 19, 53, 66, 76, 92, 132, 157, 353, 423, 559, 842, 927, 1192, 2129, 3846, 1966, 4289, 5826, 8782, 12116, 16299, 19129, 12599, 41013, 30355, 63413, 66942
Offset: 0

Views

Author

Amarnath Murthy, Jan 09 2002

Keywords

Crossrefs

Programs

  • Maple
    read("transforms"):
    A067177 := proc(n)
        local ds,k ;
        ds := A054966(2+n) ;
        for k from 0 do
            if digsum(k^3) = ds then
                return k;
            end if;
        end do:
    end proc: # R. J. Mathar, Aug 28 2018

Extensions

More terms from Sascha Kurz, Jan 28 2003

A275910 Numbers not congruent to 0, 1 or 8 mod 9.

Original entry on oeis.org

2, 3, 4, 5, 6, 7, 11, 12, 13, 14, 15, 16, 20, 21, 22, 23, 24, 25, 29, 30, 31, 32, 33, 34, 38, 39, 40, 41, 42, 43, 47, 48, 49, 50, 51, 52, 56, 57, 58, 59, 60, 61, 65, 66, 67, 68, 69, 70, 74, 75, 76, 77, 78, 79, 83, 84, 85, 86, 87, 88, 92, 93, 94, 95, 96, 97, 101, 102, 103, 104, 105, 106, 110, 111
Offset: 1

Views

Author

N. J. A. Sloane, Aug 26 2016

Keywords

References

  • H. I. Okagbue, M. O. Adamu, S. A. Bishop and A. A. Opanuga, Properties of Sequences Generated by Summing the Digits of Cubed Positive Integers, Indian Journal Of Natural Sciences, Vol. 6 / Issue 32 / October 2015.

Crossrefs

Complement of A054966.

Programs

Formula

From Colin Barker, Aug 26 2016: (Start)
a(n) = a(n-1)+a(n-6)-a(n-7) for n>7.
G.f.: x*(2+x+x^2+x^3+x^4+x^5+2*x^6) / ((1-x)^2*(1+x)*(1-x+x^2)*(1+x+x^2)). (End)
Showing 1-8 of 8 results.