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 1-4 of 4 results.

A053829 Sum of digits of (n written in base 8).

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5, 6, 7, 8, 2, 3, 4, 5, 6, 7, 8, 9, 3, 4, 5, 6, 7, 8, 9, 10, 4, 5, 6, 7, 8, 9, 10, 11, 5, 6, 7, 8, 9, 10, 11, 12, 6, 7, 8, 9, 10, 11, 12, 13, 7, 8, 9, 10, 11, 12, 13, 14, 1, 2, 3, 4, 5, 6, 7, 8, 2, 3, 4, 5, 6, 7, 8, 9, 3, 4, 5, 6, 7, 8, 9, 10, 4, 5, 6, 7, 8, 9, 10
Offset: 0

Views

Author

Henry Bottomley, Mar 28 2000

Keywords

Comments

Also the fixed point of the morphism 0->{0,1,2,3,4,5,6,7}, 1->{1,2,3,4,5,6,7,8}, 2->{2,3,4,5,6,7,8,9}, etc. - Robert G. Wilson v, Jul 27 2006

Examples

			a(20)=2+4=6 because 20 is written as 24 base 8.
From _Omar E. Pol_, Feb 21 2010: (Start)
It appears that this can be written as a triangle (See the conjecture in the entry A000120):
0,
1,2,3,4,5,6,7,
1,2,3,4,5,6,7,8,2,3,4,5,6,7,8,9,3,4,5,6,7,8,9,10,4,5,6,7,8,9,10,11,5,6,7,8,9,10,11,12,6,7,8,9,10,11,12,13,7,8,9,10,11,12,13,14,
1,2,3,4,5,6,7,8,2,3,4,5,6,7,8,9,3,4,5,6,7,8,9,10,4,5,6,7,8,9,10...
where the rows converge to A173528. (End)
		

Crossrefs

Programs

  • Haskell
    a053829 n = q 0 $ divMod n 8 where
       q r (0, d) = r + d
       q r (m, d) = q (r + d) $ divMod m 8
    -- Reinhard Zumkeller, May 15 2011
    
  • Mathematica
    Table[Plus @@ IntegerDigits[n, 8], {n, 0, 95}] (* or *)
    Nest[ Flatten[ #1 /. a_Integer -> Table[a + i, {i, 0, 7}]] &, {0}, 4] (* Robert G. Wilson v, Jul 27 2006 *)
  • PARI
    a(n)=if(n<1,0,if(n%8,a(n-1)+1,a(n/8)))
    
  • PARI
    a(n) = sumdigits(n, 8); \\ Michel Marcus, Jul 10 2022
    
  • Python
    def A053829(n): return sum(int(d) for d in oct(n)[2:]) # Chai Wah Wu, Jul 09 2022

Formula

From Benoit Cloitre, Dec 19 2002: (Start)
a(0) = 0, a(8n+i) = a(n)+i for 0 <= i <= 7.
a(n) = n-7*(Sum_{k>0} floor(n/8^k)) = n-7*A054897(n). (End)
a(n) = A138530(n,8) for n > 7. - Reinhard Zumkeller, Mar 26 2008
a(n) = Sum_k>=0 {A031045(n,k)}. - Philippe Deléham, Oct 21 2011
a(0) = 0; a(n) = a(n - 8^floor(log_8(n))) + 1. - Ilya Gutkovskiy, Aug 24 2019
Sum_{n>=1} a(n)/(n*(n+1)) = 8*log(8)/7 (Shallit, 1984). - Amiram Eldar, Jun 03 2021

A231680 a(n) = Sum_{i=0..n} digsum_8(i), where digsum_8(i) = A053829(i).

Original entry on oeis.org

0, 1, 3, 6, 10, 15, 21, 28, 29, 31, 34, 38, 43, 49, 56, 64, 66, 69, 73, 78, 84, 91, 99, 108, 111, 115, 120, 126, 133, 141, 150, 160, 164, 169, 175, 182, 190, 199, 209, 220, 225, 231, 238, 246, 255, 265, 276, 288, 294, 301, 309, 318, 328, 339, 351, 364, 371, 379, 388, 398, 409, 421, 434, 448, 449, 451, 454, 458, 463, 469, 476, 484, 486, 489, 493, 498, 504, 511, 519, 528
Offset: 0

Views

Author

N. J. A. Sloane, Nov 13 2013

Keywords

References

  • Jean-Paul Allouche and Jeffrey Shallit, Automatic sequences, Cambridge University Press, 2003, p. 94.

Crossrefs

Programs

  • Mathematica
    a[n_] := Plus @@ IntegerDigits[n, 8]; Accumulate @ Array[a, 80, 0] (* Amiram Eldar, Dec 09 2021 *)
  • PARI
    a(n) = sum(i=0, n, sumdigits(i, 8)); \\ Michel Marcus, Sep 20 2017

Formula

a(n) ~ 7*n*log(n)/(6*log(2)). - Amiram Eldar, Dec 09 2021

A231682 a(n) = Sum_{i=0..n} digsum_8(i)^3, where digsum_8(i) = A053829(i).

Original entry on oeis.org

0, 1, 9, 36, 100, 225, 441, 784, 785, 793, 820, 884, 1009, 1225, 1568, 2080, 2088, 2115, 2179, 2304, 2520, 2863, 3375, 4104, 4131, 4195, 4320, 4536, 4879, 5391, 6120, 7120, 7184, 7309, 7525, 7868, 8380, 9109, 10109, 11440, 11565, 11781, 12124, 12636, 13365, 14365, 15696, 17424, 17640, 17983, 18495, 19224, 20224, 21555, 23283, 25480, 25823, 26335, 27064, 28064, 29395
Offset: 0

Views

Author

N. J. A. Sloane, Nov 13 2013

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(i=0, n, sumdigits(i, 8)^3); \\ Michel Marcus, Sep 20 2017

A231683 a(n) = Sum_{i=0..n} digsum_8(i)^4, where digsum_8(i) = A053829(i).

Original entry on oeis.org

0, 1, 17, 98, 354, 979, 2275, 4676, 4677, 4693, 4774, 5030, 5655, 6951, 9352, 13448, 13464, 13545, 13801, 14426, 15722, 18123, 22219, 28780, 28861, 29117, 29742, 31038, 33439, 37535, 44096, 54096, 54352, 54977, 56273, 58674, 62770, 69331, 79331, 93972, 94597, 95893, 98294, 102390, 108951, 118951, 133592, 154328, 155624, 158025, 162121, 168682, 178682, 193323, 214059
Offset: 0

Views

Author

N. J. A. Sloane, Nov 13 2013

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(i=0, n, sumdigits(i, 8)^4); \\ Michel Marcus, Sep 20 2017
Showing 1-4 of 4 results.