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.

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A255437 In positive integers: replace k^2 with the first k odd numbers.

Original entry on oeis.org

1, 2, 3, 1, 3, 5, 6, 7, 8, 1, 3, 5, 10, 11, 12, 13, 14, 15, 1, 3, 5, 7, 17, 18, 19, 20, 21, 22, 23, 24, 1, 3, 5, 7, 9, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 1, 3, 5, 7, 9, 11, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 1, 3, 5, 7, 9, 11, 13, 50, 51
Offset: 1

Views

Author

Reinhard Zumkeller, Mar 23 2015

Keywords

Comments

a(A005448(n)) = 1;
conjecture: a(A068722(n)) = (2*n+1)^2, i.e. A068722(n) = gives the position of the first occurrence of n-th odd square;
A164514(n) = a(A255527(n)) and a(m) < A164514(n) for m < A255527(n).

Examples

			.  A000290 | 1,    4,          9,                      16,         . . .
.  A000027 | _,2,3,___,5,6,7,8,_____,10,11,12,13,14,15,_______,17,18,...
.  A158405 | 1,    1,3,        1,3,5,                  1,3,5,7,
.  --------+-------------------------------------------------------------
.     a(n) | 1,2,3,1,3,5,6,7,8,1,3,5,10,11,12,13,14,15,1,3,5,7,17,18,19 .
		

Crossrefs

Cf. A256188, A000290, A000037, A158405, A016742, A164514, A255527, A005448, A255507 (first differences), A255508 (partial sums).

Programs

  • Haskell
    a255437 n = a255437_list !! (n-1)
    a255437_list = f 0 [1..] a158405_tabl where
       f k xs (zs:zss) = us ++ zs ++ f (k + 2) vs zss
                         where (us, v:vs) = splitAt k xs

A164514 1 followed by numbers that are not squares.

Original entry on oeis.org

1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 24, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79
Offset: 1

Views

Author

Jaroslav Krizek, Aug 14 2009

Keywords

Comments

Complement of A000290 for n >= 1.
a(n) = A255437(A255527(n)) and A255437(m) < a(n) for m < A255527(n), i.e. record values in A255437.

Crossrefs

Programs

Formula

{1} Union A000037.
a(n) = A000037(n-1) = n-1+floor(1/2 + sqrt(n - 1)) = n-1 + floor( sqrt(n-1 + floor( sqrt(n - 1) ))) for n > 1.

Extensions

Edited by R. J. Mathar, Aug 21 2009
Showing 1-2 of 2 results.