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 1-2 of 2 results.

A256188 In positive integers: replace k*(k+1)/2 with the first k numbers.

Original entry on oeis.org

1, 2, 1, 2, 4, 5, 1, 2, 3, 7, 8, 9, 1, 2, 3, 4, 11, 12, 13, 14, 1, 2, 3, 4, 5, 16, 17, 18, 19, 20, 1, 2, 3, 4, 5, 6, 22, 23, 24, 25, 26, 27, 1, 2, 3, 4, 5, 6, 7, 29, 30, 31, 32, 33, 34, 35, 1, 2, 3, 4, 5, 6, 7, 8, 37, 38, 39, 40, 41, 42, 43, 44, 1, 2, 3, 4
Offset: 1

Views

Author

Reinhard Zumkeller, Mar 26 2015

Keywords

Comments

a(A002061(n)) = 1;
a(A253169(n)) = n and a(m) != n for m < A253169(n);
a(A000537(n)) = A000217(n) and a(m) != A000217(n) for m < A000537(n);
see A004202 and A014132 for record values greater than 1 and where they occur: A014132(n) = a(A004202(n)).

Examples

			.  A000217 | 1,  3,      6,          10,                 15,       . . .
.  A000027 | _,2,___,4,5,_____,7,8,9,_______,11,12,13,14,_________,16,...
.  A002260 | 1,  1,2,    1,2,3,      1,2,3,4,            1,2,3,4,5,
.  --------+-------------------------------------------------------------
.     a(n) | 1,2,1,2,4,5,1,2,3,7,8,9,1,2,3,4,11,12,13,14,1,2,3,4,5,16,17,...
		

Crossrefs

Cf. A255437, A000217, A014132, A002260, A000537, A004202, A014132, A002061, A255878 (first differences), A255879 (partial sums).

Programs

  • Haskell
    a256188 n = a256188_list !! (n-1)
    a256188_list = f 0 [1..] a002260_tabl where
       f k xs (zs:zss) = us ++ zs ++ f (k + 1) vs zss
                         where (us, v:vs) = splitAt k xs
  • Mathematica
    Table[If[OddQ[Sqrt[8n+1]],Range[(Sqrt[8n+1]-1)/2],n],{n,50}]//Flatten (* Harvey P. Dale, Jun 01 2019 *)

A255508 Partial sums of A255437.

Original entry on oeis.org

1, 3, 6, 7, 10, 15, 21, 28, 36, 37, 40, 45, 55, 66, 78, 91, 105, 120, 121, 124, 129, 136, 153, 171, 190, 210, 231, 253, 276, 300, 301, 304, 309, 316, 325, 351, 378, 406, 435, 465, 496, 528, 561, 595, 630, 631, 634, 639, 646, 655, 666, 703, 741, 780, 820, 861
Offset: 1

Views

Author

Reinhard Zumkeller, Mar 23 2015

Keywords

Crossrefs

Programs

  • Haskell
    a255508 n = a255508_list !! (n-1)
    a255508_list = scanl1 (+) a255437_list
Showing 1-2 of 2 results.