A230633 -id:A230633 - cp's OEIS frontend

A053737 Sum of digits of (n written in base 4).

0, 1, 2, 3, 1, 2, 3, 4, 2, 3, 4, 5, 3, 4, 5, 6, 1, 2, 3, 4, 2, 3, 4, 5, 3, 4, 5, 6, 4, 5, 6, 7, 2, 3, 4, 5, 3, 4, 5, 6, 4, 5, 6, 7, 5, 6, 7, 8, 3, 4, 5, 6, 4, 5, 6, 7, 5, 6, 7, 8, 6, 7, 8, 9, 1, 2, 3, 4, 2, 3, 4, 5, 3, 4, 5, 6, 4, 5, 6, 7, 2, 3, 4, 5, 3, 4, 5, 6, 4, 5, 6, 7, 5, 6, 7, 8, 3, 4, 5, 6, 4, 5, 6, 7, 5

Offset: 0

Henry Bottomley, Mar 28 2000

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

			a(20) = 1+1+0 = 2 because 20 is written as 110 base 4.
From _Omar E. Pol_, Feb 21 2010: (Start)
This can be written as a triangle (cf. A000120):
  0,
  1,2,3,
  1,2,3,4,2,3,4,5,3,4,5,6,
  1,2,3,4,2,3,4,5,3,4,5,6,4,5,6,7,2,3,4,5,3,4,5,6,4,5,6,7,5,6,7,8,3,4,5,6,4,5,6,7,5,6,7,8,6,7,8,9,
  1,2,3,4,2,3,4,5,3,4,5,6,4,5,6,7,2,3,4,5,3,4,5,6,4,5,6,7,5,6,7,8,3,4,5,6,4,...
where the rows converge to A173524.
(End)

Donovan Johnson, Table of n, a(n) for n = 0..10000
F. T. Adams-Watters and F. Ruskey, Generating Functions for the Digital Sum and Other Digit Counting Sequences, JIS Vol. 12 (2009), Article 09.5.6.
Steve Butler and Ron L. Graham, Shuffling with ordered cards, arXiv 1003:4422 [math.CO], 2010.
Jeffrey O. Shallit, Problem 6450, Advanced Problems, The American Mathematical Monthly, Vol. 91, No. 1 (1984), pp. 59-60; Two series, solution to Problem 6450, ibid., Vol. 92, No. 7 (1985), pp. 513-514.
Robert Walker, Self Similar Sloth Canon Number Sequences.
Eric Weisstein's World of Mathematics, Digit Sum.

Cf. A231664-A231667, A138530.
Cf. A173524. - Omar E. Pol, Feb 21 2010
Sum of digits of n written in bases 2-16: A000120, A053735, this sequence, A053824, A053827, A053828, A053829, A053830, A007953, A053831, A053832, A053833, A053834, A053835, A053836.
Related base-4 sequences: A053737, A230631, A230632, A010064, A230633, A230634, A230635, A230636, A230637, A230638, A010065 (trajectory of 1).
Cf. A007090, A239690.

a053737 n = if n == 0 then 0 else a053737 m + r where (m, r) = divMod n 4
-- Reinhard Zumkeller, Mar 19 2015

for u=0:104; sol(u+1)=sum(dec2base(u,4)-'0');end
sol % Marius A. Burtea, Jan 17 2019

[&+Intseq(n,4):n in [0..104]]; // Marius A. Burtea, Jan 17 2019

A053737 := proc(n)
    add(d,d=convert(n,base,4)) ;
end proc: # R. J. Mathar, Oct 31 2012

Table[Plus @@ IntegerDigits[n, 4], {n, 0, 100}] (* or *)
Nest[ Flatten[ #1 /. a_Integer -> {a, a+1, a+2, a+3}] &, {0}, 4] (* Robert G. Wilson v, Jul 27 2006 *)
DigitSum[Range[0, 100], 4] (* Paolo Xausa, Aug 01 2024 *)

PARI
```
a(n)=if(n<1,0,if(n%4,a(n-1)+1,a(n/4)))
```

a(n) = sumdigits(n, 4); \\ Michel Marcus, Aug 24 2019

From Benoit Cloitre, Dec 19 2002: (Start)
a(0) = 0, a(4n+i) = a(n)+i for 0 <= i <= 3.
a(n) = n - 3*Sum_{k>0} floor(n/4^k) = n - 3*A054893(n). (End)
G.f.: (Sum_{k>=0} (x^(4^k) + 2*x^(2*4^k) + 3*x^(3*4^k))/(1 + x^(4^k) + x^(2*4^k) + x^(3*4^k)))/(1-x). - Franklin T. Adams-Watters, Nov 03 2005
a(n) = A138530(n,4) for n > 3. - Reinhard Zumkeller, Mar 26 2008
a(n) = Sum_{k>=0} A030386(n,k). - Philippe Deléham, Oct 21 2011
a(n) = A007953(A007090(n)). - Reinhard Zumkeller, Mar 19 2015
a(0) = 0; a(n) = a(n - 4^floor(log_4(n))) + 1. - Ilya Gutkovskiy, Aug 23 2019
Sum_{n>=1} a(n)/(n*(n+1)) = 4*log(4)/3 (Shallit, 1984). - Amiram Eldar, Jun 03 2021

A010064 Base 4 self or Colombian numbers (not of form k + sum of base 4 digits of k).

Original entry on oeis.org

1, 3, 8, 13, 18, 20, 25, 30, 35, 37, 42, 47, 52, 54, 59, 64, 73, 78, 83, 85, 90, 95, 100, 102, 107, 112, 117, 119, 124, 129, 138, 143, 148, 150, 155, 160, 165, 167, 172, 177, 182, 184, 189, 194, 203, 208, 213, 215, 220, 225, 230, 232, 237, 242, 247, 249, 254

Offset: 1

Leonid Broukhis

Steven R. Finch, Mathematical Constants, Cambridge, 2003, Section 2.24, pp. 179-180.
József Sándor and Borislav Crstici, Handbook of Number theory II, Kluwer Academic Publishers, 2004, Chapter 4, pp. 384-386.

Donovan Johnson, Table of n, a(n) for n = 1..10000
Index entries for Colombian or self numbers and related sequences

Cf. A003052, A010061, A010067, A010070, A230631-A230635.

Related base-4 sequences: A053737, A230631, A230632, A010064, A230633, A230634,A230635, A230636, A230637, A230638, A010065 (trajectory of 1)

s[n_] := n + Plus @@ IntegerDigits[n, 4]; m = 250; Complement[Range[m], Array[s, m]] (* Amiram Eldar, Nov 28 2020 *)

A230638 Smallest number m such that u + (sum of base-4 digits of u) = m has exactly n solutions.

Original entry on oeis.org

0, 17, 16385, 16777234

Offset: 1

N. J. A. Sloane, Oct 31 2013

Indices of records in A230632: a(n) is the index of the first n in A230632.
The terms are a(1)=0, a(2)=4^2+1, a(3)=4^7+1, a(4)=4^12+17+1, a(5)=4^5368+17+1, a(6)=4^10924+16385+1, a(7)=4^5597880+16385+20. Note that a(7) breaks the pattern of the first six terms.
a(8) = 4^16777229 + 4^12 + 19.
For the leading power of 4 see A230637.

			n=2: the two solutions to u+(base-4 digit-sum of u) = 17 are 13 and 16.
n=3: the three solutions to u+(base-4 digit-sum of u) = 4^7+1 are 4^7, 4^7-15, 4^7-18.
n=4: the four solutions to u+(base-4 digit-sum of u) = 4^12+17+1 are 4^12+{16, 13, -14, -17}.

Max Alekseyev, Table of expressions for a(n), for n=1..100
Max A. Alekseyev and N. J. A. Sloane, On Kaprekar's Junction Numbers, arXiv:2112.14365, 2021; Journal of Combinatorics and Number Theory 12:3 (2022), 115-155.
Index entries for Colombian or self numbers and related sequences

Cf. A230637.
Related base-4 sequences:  A053737, A230631, A230632, A010064, A230633, A230634, A230635, A230636, A230637, A230638, A010065 (trajectory of 1)
Smallest number m such that u + (sum of base-b digits of u) = m has exactly n solutions, for bases 2 through 10: A230303, A230640, A230638, A230867, A238840, A238841, A238842, A238843, A006064.

a(8) from Max Alekseyev, Oct 31 2013

A010065 a(n+1) = a(n) + sum of digits in base 4 representation of a(n), with a(0) = 1.

Original entry on oeis.org

1, 2, 4, 5, 7, 11, 16, 17, 19, 23, 28, 32, 34, 38, 43, 50, 55, 62, 70, 74, 79, 86, 91, 98, 103, 110, 118, 125, 133, 137, 142, 149, 154, 161, 166, 173, 181, 188, 196, 200, 205, 212, 217, 224, 229, 236, 244, 251, 262, 266, 271, 278, 283, 290, 295

Offset: 0

Leonid Broukhis

S. R. Finch, Mathematical Constants, Cambridge, 2003, Section 2.24.

Donovan Johnson, Table of n, a(n) for n = 0..10000
Index entries for Colombian or self numbers and related sequences

Cf. A003052, A010061, A010062, A010064, A004207.

Related base-4 sequences: A053737, A230631, A230632, A010064, A230633, A230634, A230635, A230636, A230637, A230638, A010065 (trajectory of 1)

a010065 n = a010065_list !! n
a010065_list = iterate a230631 1  -- Reinhard Zumkeller, Mar 20 2015

a(n+1) = A230631(a(n)). - Reinhard Zumkeller, Mar 20 2015

More terms from Neven Juric, Apr 11 2008

A230632 Number of integers m such that m + (sum of digits in base-4 representation of m) = n.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 2, 0, 2, 0, 2, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 2, 0, 2, 0, 2, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 2, 0, 2, 0, 2, 1, 1, 1, 0, 1, 1, 1, 1, 0, 2, 1, 2, 1, 1, 2, 1, 2, 0, 1, 1, 1, 1, 0, 1, 1, 1, 2, 0, 2, 0, 2, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 2, 0, 2, 0

Offset: 0

N. J. A. Sloane, Oct 30 2013

Number of occurrences of n in A230631.

Donovan Johnson, Table of n, a(n) for n = 0..10000
Index entries for Colombian or self numbers and related sequences

Cf. A230631, A010064 (positions of 0's), A230633-A230635.

Related base-4 sequences: A053737, A230631, A230632, A010064, A230633, A230634,A230635, A230636, A230637, A230638, A010065 (trajectory of 1)

A230631 a(n) = n + (sum of digits in base-4 representation of n).

Original entry on oeis.org

0, 2, 4, 6, 5, 7, 9, 11, 10, 12, 14, 16, 15, 17, 19, 21, 17, 19, 21, 23, 22, 24, 26, 28, 27, 29, 31, 33, 32, 34, 36, 38, 34, 36, 38, 40, 39, 41, 43, 45, 44, 46, 48, 50, 49, 51, 53, 55, 51, 53, 55, 57, 56, 58, 60, 62, 61, 63, 65, 67, 66, 68, 70, 72, 65, 67, 69, 71, 70, 72, 74, 76, 75, 77, 79, 81, 80, 82, 84, 86, 82

Offset: 0

N. J. A. Sloane, Oct 30 2013

Donovan Johnson, Table of n, a(n) for n = 0..10000
Index entries for Colombian or self numbers and related sequences

Cf. A010064 (missing numbers), A230632 (number of inverses), A230633-A230635.

Related base-4 sequences: A053737, A230632, A010064, A230633, A230634, A230635, A230636, A230637, A230638, A010065 (trajectory of 1)

a230631 n = a053737 n + n  -- Reinhard Zumkeller, Mar 20 2015

apply( {A230631(n)=n+sumdigits(n,4)}, [0..99]) \\ M. F. Hasler, Oct 30 2024

a(n) = A053737(n) + n. - Reinhard Zumkeller, Mar 20 2015

A230634 Numbers n such that m + (sum of digits in base-4 representation of m) = n has exactly two solutions.

Original entry on oeis.org

17, 19, 21, 34, 36, 38, 51, 53, 55, 65, 67, 70, 72, 82, 84, 86, 99, 101, 103, 116, 118, 120, 130, 132, 135, 137, 147, 149, 151, 164, 166, 168, 181, 183, 185, 195, 197, 200, 202, 212, 214, 216, 229, 231, 233, 246, 248, 250, 257, 261, 262, 263, 267, 274, 276, 278, 291, 293, 295, 308, 310, 312, 322, 324, 327, 329, 339

Offset: 1

N. J. A. Sloane, Oct 30 2013

Donovan Johnson, Table of n, a(n) for n = 1..10000
Index entries for Colombian or self numbers and related sequences

Related base-4 sequences: A053737, A230631, A230632, A010064, A230633, A230634, A230635, A230636, A230637, A230638, A010065 (trajectory of 1)

etsQ[n_]:=Count[#+Total[IntegerDigits[#,4]]&/@Range[n-1],n]==2; Select[ Range[ 350],etsQ] (* Harvey P. Dale, May 25 2016 *)

A230635 Numbers n such that m + (sum of digits in base-4 representation of m) = n has exactly three solutions.

Original entry on oeis.org

16385, 16387, 16402, 16404, 32770, 32772, 32787, 32789, 49155, 49157, 49172, 49174, 65542, 65554, 81922, 81924, 81939, 81941, 98307, 98309, 98324, 98326, 114692, 114694, 114709, 114711, 131079, 131091, 147459, 147461, 147476, 147478, 163844, 163846, 163861

Offset: 1

N. J. A. Sloane, Oct 30 2013

Donovan Johnson, Table of n, a(n) for n = 1..10000
Index entries for Colombian or self numbers and related sequences

Related base-4 sequences: A053737, A230631, A230632, A010064, A230633, A230634, A230635, A230636, A230637, A230638, A010065 (trajectory of 1)

A230636 Numbers n such that m + (sum of digits in base-4 representation of m) = n has exactly four solutions.

Original entry on oeis.org

16777234, 33554451, 50331668, 83886099, 100663316, 117440533, 150994964, 167772181, 184549398, 218103829, 234881046, 251658263, 268435476, 268435478, 285212691, 301989908, 318767125, 352321556, 369098773, 385875990, 419430421, 436207638, 452984855, 486539286

Offset: 1

Donovan Johnson and N. J. A. Sloane, Oct 31 2013

Donovan Johnson, Table of n, a(n) for n = 1..10000
Index entries for Colombian or self numbers and related sequences

Related base-4 sequences: A053737, A230631, A230632, A010064, A230633, A230634, A230635, A230636, A230637, A230638, A010065 (trajectory of 1)

A230637 Leading power of 4 in A230638.

Original entry on oeis.org

2, 7, 12, 5468, 10924, 5597880, 16777229

Offset: 2

N. J. A. Sloane, Oct 31 2013

a(9) = ( 4^5468 + 2*4^12 + 39 ) / 3.
a(10) = 4^5468 + 13.
a(11) = ( 4^10924 + 2*4^5468 + 16407 ) / 3.
a(12) = 4^10924 + 10925
a(13) = ( 4^5597880 + 3*4^10924 + 32793 ) / 3.
a(14) = ( 2*4^5597880 + 32812 ) / 3.
a(15) = ( 4^16777229 + 4^5597880 + 2*4^12 + 16427 ) / 3.
a(16) = ( 2*4^16777229 + 4^13 + 42 ) / 3.

Max Alekseyev, Table n, expression for a(n) for n=2..100
Max A. Alekseyev and N. J. A. Sloane, On Kaprekar's Junction Numbers, arXiv:2112.14365, 2021; Journal of Combinatorics and Number Theory 12:3 (2022), 115-155.
Index entries for Colombian or self numbers and related sequences

Cf. A230638.

Related base-4 sequences: A053737, A230631, A230632, A010064, A230633, A230634, A230635, A230636, A230637, A230638, A010065 (trajectory of 1)

Terms a(8) onward from Max Alekseyev, Oct 31 2013

cp's OEIS Frontend

A053737 Sum of digits of (n written in base 4).

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A010064 Base 4 self or Colombian numbers (not of form k + sum of base 4 digits of k).

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A230638 Smallest number m such that u + (sum of base-4 digits of u) = m has exactly n solutions.

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A010065 a(n+1) = a(n) + sum of digits in base 4 representation of a(n), with a(0) = 1.

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A230632 Number of integers m such that m + (sum of digits in base-4 representation of m) = n.

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A230631 a(n) = n + (sum of digits in base-4 representation of n).

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A230634 Numbers n such that m + (sum of digits in base-4 representation of m) = n has exactly two solutions.

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A230635 Numbers n such that m + (sum of digits in base-4 representation of m) = n has exactly three solutions.

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A230636 Numbers n such that m + (sum of digits in base-4 representation of m) = n has exactly four solutions.

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