A263109 -id:A263109 - cp's OEIS frontend

A254524 n is the a(n)-th positive integer having its digitsum.

1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 3, 3, 3, 3, 3, 3, 3, 3, 2, 1, 4, 4, 4, 4, 4, 4, 4, 3, 2, 1, 5, 5, 5, 5, 5, 5, 4, 3, 2, 1, 6, 6, 6, 6, 6, 5, 4, 3, 2, 1, 7, 7, 7, 7, 6, 5, 4, 3, 2, 1, 8, 8, 8, 7, 6, 5, 4, 3, 2, 1, 9, 9, 8, 7, 6, 5, 4, 3, 2, 1, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 3, 4, 5, 6, 7, 8, 9, 10, 11, 10, 5

Offset: 1

David A. Corneth, Jan 31 2015

a(A051885(n)) = 1. - Reinhard Zumkeller, Oct 09 2015

Ordinal transform of A007953. - Antti Karttunen, May 20 2017

			35 is the 4th positive integer having digitsum 8 (the others before are 8, 17 and 26) so a(35) = 4.

David A. Corneth, Table of n, a(n) for n = 1..10000

Cf. A007953, A051885, A069877, A143164, A263017, A263109, A263110.

Cf. A286478 (analogous sequence for factorial base).

import Data.IntMap (empty, findWithDefault, insert)
a254524 n = a254524_list !! (n-1)
a254524_list = f 1 empty where
   f x m = y : f (x + 1) (insert q (y + 1) m) where
           y = findWithDefault 1 q m; q = a007953 x
-- Reinhard Zumkeller, Oct 09 2015

c[n_, k_] := If[n >= k, Binomial[n, k], 0]; b[s_, q_, n_] := (s1 = q; If[s <= q*(n - 1), s1 = s + q; Sum[(-1)^i*c[q, i]*c[s1 - 1 - n*i, q - 1], {i, 0, q - 1}], 0]); a[n_] := (r = 1; v = IntegerDigits[n]; l = v[[-1]]; For[i = Length[v] - 1, i >= 1, i--, For[j = 1, j <= v[[i]], j++, r += b[l + j, Length[v] - i, 10]]; l += v[[i]]]; r); Table[a[n], {n, 1, 110}] (* Jean-François Alcover, Nov 14 2016, adapted from PARI *)
With[{nn=400},#[[3]]&/@Sort[Flatten[Table[Flatten[#,1]&/@MapIndexed[ List,Select[ Table[{n,Total[IntegerDigits[n]]},{n,nn}],#[[2]]==k&]],{k,nn}],1]]](* Harvey P. Dale, Mar 29 2020 *)

\\This algorithm needs a modified binomial.
C(n, k)=if(n>=k, binomial(n, k), 0)
\\ways to roll s-q with q dice having sides 0 through n - 1.
b(s, q, n)=if(s<=q*(n-1), s+=q; sum(i=0, q-1, (-1)^i*C(q, i)*C(s-1-n*i, q-1)), 0)
\\main algorithm
a(n)={r = 1; v=digits(n); l=v[#v]; forstep(i = #v-1, 1, -1, for(j=1,v[i], r+=b(l+j, #v-i,10)); l+=v[i]);r}

A263017 n is the a(n)-th positive integer having its binary weight.

Original entry on oeis.org

1, 2, 1, 3, 2, 3, 1, 4, 4, 5, 2, 6, 3, 4, 1, 5, 7, 8, 5, 9, 6, 7, 2, 10, 8, 9, 3, 10, 4, 5, 1, 6, 11, 12, 11, 13, 12, 13, 6, 14, 14, 15, 7, 16, 8, 9, 2, 15, 17, 18, 10, 19, 11, 12, 3, 20, 13, 14, 4, 15, 5, 6, 1, 7, 16, 17, 21, 18, 22, 23, 16, 19, 24, 25, 17

Offset: 1

Paul Tek, Oct 07 2015

Binary weight is given by A000120.
a(2^k) = k+1 for any k>=0.
a(2^k-1) = 1 for any k>0.
a(A057168(k)) = a(k)+1 for any k>0.
a(A036563(k+1)) = k for any k>0.
Ordinal transform of A000120. - Alois P. Heinz, Dec 23 2018

			The numbers with binary weight 3 are: 7, 11, 13, 14, 19, ...
Hence: a(7)=1, a(11)=2, a(13)=3, a(14)=4, a(19)=5, ...
And more generally: a(A014311(k))=k for any k>0.

Paul Tek, Table of n, a(n) for n = 1..10000
Paul Tek, PERL program for this sequence

One more than A068076.
Cf. A000120, A036563, A057168, A254524, A286478, A286552, A286554, A286558.
Cf. A263109, A263110.

import Data.IntMap (empty, findWithDefault, insert)
a263017 n = a263017_list !! (n-1)
a263017_list = f 1 empty where
   f x m = y : f (x + 1) (insert h (y + 1) m) where
           y = findWithDefault 1 h m
           h = a000120 x
-- Reinhard Zumkeller, Oct 09 2015

a:= proc() option remember; local a, b, t; b, a:=
      proc() 0 end, proc(n) option remember; a(n-1);
        t:= add(i, i=convert(n, base, 2)); b(t):= b(t)+1
      end; a(0):=0; a
    end():
seq(a(n), n=1..120);  # Alois P. Heinz, Dec 23 2018

Perl
```
# See Links section.
```

from math import comb
def A263017(n):
    c, k = 1, 0
    for i,j in enumerate(bin(n)[-1:1:-1]):
        if j == '1':
            k += 1
            c += comb(i,k)
    return c # Chai Wah Wu, Mar 01 2023

a(n) = 1 + A068076(n). - Antti Karttunen, May 22 2017

A263110 n is the a(n)-th positive integer having its digitsum in base-16 representation.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 2, 1, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 4, 3, 2, 1, 6, 6, 6, 6, 6, 6, 6

Offset: 1

Reinhard Zumkeller, Oct 09 2015

Ordinal transform of A053836. - Alois P. Heinz, Dec 23 2018

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Hexadecimal
Eric Weisstein's World of Mathematics, Digit Sum
Wikipedia, Hexadecimal
Wikipedia, Digit sum

Cf. A053836, A254524, A263017, A263109.

import Data.IntMap (empty, findWithDefault, insert)
a263110 n = a263110_list !! (n-1)
a263110_list = f 1 empty where
   f x m = y : f (x + 1) (insert q (y + 1) m) where
           y = findWithDefault 1 q m; q = a053836 x

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A254524 n is the a(n)-th positive integer having its digitsum.

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A263017 n is the a(n)-th positive integer having its binary weight.

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A263110 n is the a(n)-th positive integer having its digitsum in base-16 representation.

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Haskell