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.

A183301 Complement of A014105.

Original entry on oeis.org

1, 2, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 79, 80, 81, 82, 83, 84, 85, 86
Offset: 1

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Author

Clark Kimberling, Jan 03 2011

Keywords

Crossrefs

Programs

  • Mathematica
    a=2; b=1;
    F[n_]:=a*n^2+b*n;
    R[n_]:=(n/a+((b-1)/(2a))^2)^(1/2);
    G[n_]:=n-1+Ceiling[R[n]-(b-1)/(2a)];
    Table[G[n], {n,100}]
  • Python
    from math import isqrt
    def A183301(n): return n+isqrt(n-1>>1) # Chai Wah Wu, Nov 04 2024

Formula

a(n) = n + floor(sqrt((n-1)/2)) = n + A339183(n-1). - Aaron J Grech, Jul 30 2024

A339184 Number of partitions of n into two parts such that the larger part is a nonzero square.

Original entry on oeis.org

0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3
Offset: 0

Views

Author

Wesley Ivan Hurt, Nov 26 2020

Keywords

Examples

			a(8) = 1; The partitions of 8 into 2 parts are (7,1), (6,2), (5,3) and (4,4). Since 4 is the only nonzero square appearing as a largest part, a(8) = 1.
a(9) = 0; The partitions of 9 into 2 parts are (8,1), (7,2), (6,3) and (5,4). Since there are no nonzero squares among the largest parts, a(9) = 0.
		

Crossrefs

Cf. A010052, A339183 (smaller part is a nonzero square), A339186 (total nonzero squares).

Programs

  • Mathematica
    Table[Sum[Floor[Sqrt[n - i]] - Floor[Sqrt[n - i - 1]] , {i, Floor[n/2]}], {n, 0, 100}]

Formula

a(n) = Sum_{i=1..floor(n/2)} c(n-i), where c is the square characteristic (A010052).
a(n) = Sum_{i=floor((n-1)/2)..n-2} c(i+1), where c is the square characteristic (A010052).
a(n) = A339186(n) - A339183(n).

A339186 Total number of nonzero squares in the partitions of n into 2 parts.

Original entry on oeis.org

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

Views

Author

Wesley Ivan Hurt, Nov 26 2020

Keywords

Examples

			a(8) = 3; The partitions of 8 into two parts are (7,1), (6,2), (5,3) and (4,4). There are 3 total nonzero squares among the parts (namely 1, 4 and 4 ), so a(8) = 3.
a(9) = 2; The partitions of 9 into two parts are (8,1), (7,2), (6,3) and (5,4). Since 1 and 4 are the only nonzero squares among all parts, a(9) = 2.
		

Crossrefs

Cf. A339183 (number of smaller parts), A339184 (number of larger parts).

Programs

  • Mathematica
    Table[Sum[Floor[Sqrt[i]] - Floor[Sqrt[i - 1]] + Floor[Sqrt[n - i]] - Floor[Sqrt[n - i - 1]], {i, Floor[n/2]}], {n, 0, 100}]

Formula

a(n) = A339184(n) + A339183(n).
Showing 1-3 of 3 results.