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 1-3 of 3 results.

A060857 Describe all the numbers already used (sorted into increasing order - not splitting numbers up into their digits).

Original entry on oeis.org

1, 11, 31, 4113, 612314, 8112332416, 1113253342618, 131528344153628111, 1617210364354648211113, 181921239445661758110311213116, 2211121431146586276829210411112313216118
Offset: 0

Views

Author

Henry Bottomley, May 03 2001

Keywords

Examples

			One; one one; three ones; four ones, one three; six ones, two threes, one four; eight ones, one two, three threes, two fours, one six; eleven ones, three twos, five threes, three fours, two sixes, one eight; thirteen [note not 15] ones, five twos, eight threes, four fours, one five, three sixes, two eights, one eleven [note than numbers >9 are preserved as wholes rather than as a collection of digits]; etc.
		

Crossrefs

This is a combination of methods used in A005151 and A045982. The first word of each term (the number of ones used earlier) seems to be equal to A030711 and A030761.

Programs

  • Haskell
    import Data.List (group, sort, transpose)
    a060857 n = a060857_list !! n
    a060857_list = 1 : f [1] :: [Integer] where
       f xs = (read $ concatMap show ys) : f (xs ++ ys) where
              ys = concat $ transpose [map length zss, map head zss]
              zss = group $ sort xs
    -- Reinhard Zumkeller, Jan 25 2014
    
  • Mathematica
    FromDigits /@ Nest[Append[#, Flatten@ Map[Reverse, Tally@ Sort@ Flatten@ # ] ] &, {{1}}, 10] (* Michael De Vlieger, Jul 15 2020 *)
  • Python
    def summarize_lst(lst):
      ans = []
      for d in sorted(set(lst)): ans += [lst.count(d), d]
      return ans
    def aupton(nn):
      alst, arunninglst = [1], [1]
      for n in range(nn):
        nxt_lst = summarize_lst(arunninglst)
        arunninglst += nxt_lst
        alst.append(int("".join(map(str, nxt_lst))))
      return alst
    print(aupton(10)) # Michael S. Branicky, Jan 11 2021

A030761 Record values in A030757.

Original entry on oeis.org

1, 3, 4, 6, 8, 11, 13, 16, 18, 22, 25, 28, 30, 35, 38, 42, 45, 50, 52, 56, 59, 64, 66, 71, 77, 82, 87, 91, 95, 97, 102, 107, 111, 116, 121, 125, 128, 135, 139, 143, 147, 152, 158, 161, 166, 172, 178, 184, 188, 194, 198, 205, 209, 216, 222, 227, 232, 237, 242
Offset: 1

Views

Author

Keywords

Comments

Is this the same as A030711? [From R. J. Mathar, Oct 23 2008]
Almost certainly a duplicate based on how these sequences are constructed, they are definitely the same for the first 2000 terms. - Sean A. Irvine, Apr 08 2020

Extensions

More terms and simpler title from Sean A. Irvine, Apr 08 2020

A030712 Positions of records in A030707.

Original entry on oeis.org

1, 3, 4, 6, 9, 14, 20, 28, 37, 49, 64, 81, 99, 121, 145, 172, 202, 236, 272, 311, 353, 399, 447, 499, 556, 617, 682, 750, 821, 894, 971, 1052, 1136, 1224, 1316, 1411, 1510, 1615, 1723, 1834, 1948, 2067, 2191, 2317, 2447, 2583, 2725, 2872, 3022, 3177, 3335
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A030711.

Extensions

More terms and simpler title from Sean A. Irvine, Apr 06 2020
Showing 1-3 of 3 results.