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 1-10 of 76 results. Next

A093851 a(n) = A002283(n-1) + floor(A052268(n)/(1+n)).

Original entry on oeis.org

4, 39, 324, 2799, 24999, 228570, 2124999, 19999999, 189999999, 1818181817, 17499999999, 169230769229, 1642857142856, 15999999999999, 156249999999999, 1529411764705881, 14999999999999999, 147368421052631577, 1449999999999999999, 14285714285714285713
Offset: 1

Views

Author

Amarnath Murthy, Apr 18 2004

Keywords

Comments

The first column r=1 of a triangle defined by T(n,r) = 10^(n-1) -1 + r*floor(9*10^(n-1)/(n+1)).
A row starts with a (virtual) 0th column of a rep-9-digit and fills the remainder with n+1 numbers in arithmetic progression with the largest step such that all numbers in the n-th row are n-digit numbers.

Examples

			The triangle starts in row n=1 as
4 9 # -1, -1+5, -1+2*5
39 69 99 # 9,9+30,9+2*30
324 549 774 999 # 99, 99+225, 99+2*225, 99+3*225
2799 4599 6399 8199 9999 # 999, 999+1800, 999+2*1800,..
...
The sequence contains the first column.
		

Crossrefs

Programs

  • Magma
    [10^(n-1) -1 +Floor(9*10^(n-1)/(n+1)): n in [1..20]]; // G. C. Greubel, Apr 02 2019
    
  • Maple
    A093851 := proc(n) 10^(n-1)-1+floor(9*10^(n-1)/(n+1)) ; end proc: seq(A093851(n),n=1..20) ; # R. J. Mathar, Oct 14 2010
  • Mathematica
    Table[10^(n-1) -1 +Floor[9*10^(n-1)/(n+1)], {n, 1, 20}] (* G. C. Greubel, Apr 02 2019 *)
  • PARI
    {a(n) = 10^(n-1) -1 +floor(9*10^(n-1)/(n+1))}; \\ G. C. Greubel, Apr 02 2019
    
  • Sage
    [10^(n-1) -1 +floor(9*10^(n-1)/(n+1)) for n in (1..20)] # G. C. Greubel, Apr 02 2019

Formula

a(n) = 10^(n-1) -1 + floor(9*10^(n-1)/(n+1)). - G. C. Greubel, Apr 02 2019

Extensions

More terms from R. J. Mathar, Oct 14 2010

A181354 Number of n-digit perfect cubes.

Original entry on oeis.org

2, 2, 5, 12, 25, 53, 116, 249, 535, 1155, 2487, 5358, 11545, 24871, 53584, 115444, 248715, 535841, 1154435, 2487154, 5358411, 11544347, 24871542, 53584111, 115443470, 248715414, 535841116, 1154434691, 2487154143, 5358411166
Offset: 1

Views

Author

Martin Renner, Jan 28 2011

Keywords

Comments

a(n) is also the total number of n-digit numbers requiring 1 positive cube in their representation as sum of cubes.
a(n) + A181376(n) + A181378(n) + A181380(n) + A181384(n) + A181401(n) + A181403(n) + A181405(n) + A171386(n) = A052268(n).
Differs from A062941 only at n=1, because 0 is considered a 0-digit, not a 1-digit number here. - R. J. Mathar, Jul 09 2011

Crossrefs

Programs

  • Maple
    a:=n->ceil(10^(n/3))-ceil(10^((n-1)/3));
  • Mathematica
    With[{c = Range[4650000]^3}, Length[#]&/@Table[Select[c, IntegerLength[#] == n &], {n, 20}]] (* Harvey P. Dale, Feb 01 2011 *)
    Differences[Ceiling[10^(Range[0, 30]/3)]]

Formula

a(n) = A061439(n) - A061439(n-1).

Extensions

More terms from T. D. Noe, Feb 01 2011

A186654 Total number of n-digit numbers requiring 4 positive biquadrates in their representation as sum of biquadrates.

Original entry on oeis.org

1, 6, 41, 298, 2720, 24688, 232970, 2255588, 22228377, 220476980, 2197066826
Offset: 1

Views

Author

Martin Renner, Feb 25 2011

Keywords

Comments

A102831(n) + A186650(n) + A186652(n) + a(n) + A186656(n) + A186658(n) + A186660(n) + A186662(n) + A186664(n) + A186666(n) + A186668(n) + A186670(n) + A186672(n) + A186674(n) + A186676(n) + A186678(n) + A186681(n) + A186683(n) + A186685(n) = A052268(n), for n>1.

Crossrefs

Formula

a(n) = A186653(n) - A186653(n-1).

Extensions

a(5)-a(11) from Giovanni Resta, Apr 26 2016

A186656 Total number of n-digit numbers requiring 5 positive biquadrates in their representation as sum of biquadrates.

Original entry on oeis.org

1, 6, 60, 587, 7277, 91470, 1151734, 14116900, 166220264, 1888964884, 20910204634
Offset: 1

Views

Author

Martin Renner, Feb 25 2011

Keywords

Comments

A102831(n) + A186650(n) + A186652(n) + A186654(n) + a(n) + A186658(n) + A186660(n) + A186662(n) + A186664(n) + A186666(n) + A186668(n) + A186670(n) + A186672(n) + A186674(n) + A186676(n) + A186678(n) + A186681(n) + A186683(n) + A186685(n) = A052268(n), for n>1.

Crossrefs

Formula

a(n) = A186655(n) - A186655(n-1).

Extensions

a(5)-a(11) from Giovanni Resta, Apr 29 2016

A186658 Total number of n-digit numbers requiring 6 positive biquadrates in their representation as sum of biquadrates.

Original entry on oeis.org

1, 6, 71, 877, 11437, 140179, 1567562, 16444269, 158993052, 1448222849, 12807964358
Offset: 1

Views

Author

Martin Renner, Feb 25 2011

Keywords

Comments

A102831(n) + A186650(n) + A186652(n) + A186654(n) + A186656(n) + a(n) + A186660(n) + A186662(n) + A186664(n) + A186666(n) + A186668(n) + A186670(n) + A186672(n) + A186674(n) + A186676(n) + A186678(n) + A186681(n) + A186683(n) + A186685(n) = A052268(n), for n>1.

Crossrefs

Formula

a(n) = A186657(n) - A186657(n-1).

Extensions

a(5)-a(11) from Giovanni Resta, Apr 29 2016

A186660 Total number of n-digit numbers requiring 7 positive biquadrates in their representation as sum of biquadrates.

Original entry on oeis.org

1, 5, 77, 1018, 11712, 122460, 1107703, 8829638, 71681321, 638559445, 6064719750
Offset: 1

Views

Author

Martin Renner, Feb 25 2011

Keywords

Comments

A102831(n) + A186650(n) + A186652(n) + A186654(n) + A186656(n) + A186658(n) + a(n) + A186662(n) + A186664(n) + A186666(n) + A186668(n) + A186670(n) + A186672(n) + A186674(n) + A186676(n) + A186678(n) + A186681(n) + A186683(n) + A186685(n) = A052268(n), for n>1.

Crossrefs

Formula

a(n) = A186659(n) - A186659(n-1).

Extensions

a(5)-a(11) from Giovanni Resta, Apr 29 2016

A186662 Total number of n-digit numbers requiring 8 positive biquadrates in their representation as sum of biquadrates.

Original entry on oeis.org

1, 5, 77, 975, 9457, 83959, 700406, 6220793, 60225898, 600223995, 6000225272
Offset: 1

Views

Author

Martin Renner, Feb 25 2011

Keywords

Comments

A102831(n) + A186650(n) + A186652(n) + A186654(n) + A186656(n) + A186658(n) + A186660(n) + a(n) + A186664(n) + A186666(n) + A186668(n) + A186670(n) + A186672(n) + A186674(n) + A186676(n) + A186678(n) + A186681(n) + A186683(n) + A186685(n) = A052268(n), for n>1.

Crossrefs

Formula

a(n) = A186661(n) - A186661(n-1).

Extensions

a(5)-a(11) from Giovanni Resta, Apr 29 2016

A186664 Total number of n-digit numbers requiring 9 positive biquadrates in their representation as sum of biquadrates.

Original entry on oeis.org

1, 5, 72, 842, 7755, 68550, 614030, 6014243, 60013964, 600013863, 6000013912
Offset: 1

Views

Author

Martin Renner, Feb 25 2011

Keywords

Comments

A102831(n) + A186650(n) + A186652(n) + A186654(n) + A186656(n) + A186658(n) + A186660(n) + A186662(n) + a(n) + A186666(n) + A186668(n) + A186670(n) + A186672(n) + A186674(n) + A186676(n) + A186678(n) + A186681(n) + A186683(n) + A186685(n) = A052268(n), for n>1.

Crossrefs

Formula

a(n) = A186663(n) - A186663(n-1).

Extensions

a(5)-a(11) from Giovanni Resta, Apr 29 2016

A186666 Total number of n-digit numbers requiring 10 positive biquadrates in their representation as sum of biquadrates.

Original entry on oeis.org

0, 6, 66, 740, 7064, 62754, 602728, 6002740, 60002625, 600002765, 6000002823
Offset: 1

Views

Author

Martin Renner, Feb 25 2011

Keywords

Comments

A102831(n) + A186650(n) + A186652(n) + A186654(n) + A186656(n) + A186658(n) + A186660(n) + A186662(n) + A186664(n) + a(n) + A186668(n) + A186670(n) + A186672(n) + A186674(n) + A186676(n) + A186678(n) + A186681(n) + A186683(n) + A186685(n) = A052268(n), for n>1.

Crossrefs

Formula

a(n) = A186665(n) - A186665(n-1).

Extensions

a(5)-a(11) from Giovanni Resta, Apr 29 2016

A186668 Total number of n-digit numbers requiring 11 positive biquadrates in their representation as sum of biquadrates.

Original entry on oeis.org

0, 6, 64, 690, 6674, 60914, 600941, 6000995, 60000942, 600000942, 6000000909
Offset: 1

Views

Author

Martin Renner, Feb 25 2011

Keywords

Comments

A102831(n) + A186650(n) + A186652(n) + A186654(n) + A186656(n) + A186658(n) + A186660(n) + A186662(n) + A186664(n) + A186666(n) + a(n) + A186670(n) + A186672(n) + A186674(n) + A186676(n) + A186678(n) + A186681(n) + A186683(n) + A186685(n) = A052268(n), for n>1.

Crossrefs

Formula

a(n) = A186667(n) - A186667(n-1).

Extensions

a(5)-a(11) from Giovanni Resta, Apr 29 2016
Showing 1-10 of 76 results. Next