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 1-7 of 7 results.

A122793 Connell sum sequence (partial sums of the Connell sequence).

Original entry on oeis.org

1, 3, 7, 12, 19, 28, 38, 50, 64, 80, 97, 116, 137, 160, 185, 211, 239, 269, 301, 335, 371, 408, 447, 488, 531, 576, 623, 672, 722, 774, 828, 884, 942, 1002, 1064, 1128, 1193, 1260, 1329, 1400, 1473, 1548, 1625, 1704, 1785, 1867, 1951, 2037, 2125, 2215, 2307, 2401, 2497, 2595, 2695, 2796, 2899, 3004, 3111, 3220
Offset: 1

Views

Author

Grady Bullington (bullingt(AT)uwosh.edu), Sep 14 2006

Keywords

Comments

a(n) is the sum of the n highest entries in the projection of the n-th tetrahedron or tetrahedral number (e.g., a(7) = 7+6+6+5+5+5+4+4).
a(n) is a sharp upper bound for the value of a gamma-labeling of a graph with n edges (cf. Bullington).

Crossrefs

Cf. A337300 (geometric Connell sums).

Programs

  • Python
    from math import isqrt
    def A122793(n): return n*(n+1)-(r:=(k:=isqrt(m:=n<<1))+int((m<<2)>(k<<2)*(k+1)+1))*((6*n+1)-r**2)//6 # Chai Wah Wu, Jul 26 2022

Formula

a(n) = (n-th triangular number) - n + (n-th partial sum of A122797).
a(n) = n^2 + n - R*((6*n+1)-R^2)/6, where R = round(sqrt(2*n)). - Gerald Hillier, Nov 29 2009

A122800 A P_4-stuttered arithmetic progression with a(n+1)=a(n) if n is square, a(n+1)=a(n)+2 otherwise.

Original entry on oeis.org

1, 1, 3, 5, 5, 7, 9, 11, 13, 13, 15, 17, 19, 21, 23, 25, 25, 27, 29, 31, 33, 35, 37, 39, 41, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 145, 147, 149, 151, 153, 155, 157, 159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179, 181
Offset: 1

Views

Author

Grady Bullington (bullingt(AT)uwosh.edu), Sep 14 2006

Keywords

Comments

P_4(i) = the i-th square.

Crossrefs

Programs

  • Mathematica
    nxt[{n_,a_}]:={n+1,If[IntegerQ[Sqrt[n+1]],a,a+2]}; NestList[nxt,{0,1},100][[All,2]] (* Harvey P. Dale, Jan 01 2020 *)
  • PARI
    lista(m) = {aa = 1; for (i=1, m, print1(aa, ", "); if (! issquare(i), aa = aa + 2););} \\ Michel Marcus, Apr 01 2013

Formula

a(n) = A045928(n)-n+1.

A122794 Connell (3,2)-sum sequence (partial sums of the (3,2)-Connell sequence).

Original entry on oeis.org

1, 3, 8, 16, 25, 37, 52, 70, 91, 113, 138, 166, 197, 231, 268, 308, 349, 393, 440, 490, 543, 599, 658, 720, 785, 851, 920, 992, 1067, 1145, 1226, 1310, 1397, 1487, 1580, 1676, 1773, 1873, 1976, 2082, 2191, 2303, 2418, 2536, 2657, 2781, 2908, 3038, 3171, 3305, 3442, 3582, 3725, 3871, 4020, 4172, 4327, 4485, 4646, 4810, 4977, 5147, 5320, 5496, 5673, 5853, 6036, 6222, 6411, 6603
Offset: 1

Views

Author

Grady Bullington (bullingt(AT)uwosh.edu), Sep 14 2006

Keywords

Crossrefs

Formula

a(n) = (n-th triangular number)-n+(n-th partial sum of A122800).

A122795 Connell (5,3)-sum sequence (partial sums of the (5,3)-Connell sequence).

Original entry on oeis.org

1, 3, 10, 22, 39, 57, 80, 108, 141, 179, 222, 270, 319, 373, 432, 496, 565, 639, 718, 802, 891, 985, 1080, 1180, 1285, 1395, 1510, 1630, 1755, 1885, 2020, 2160, 2305, 2455, 2610, 2766, 2927, 3093, 3264, 3440, 3621, 3807, 3998, 4194, 4395, 4601, 4812, 5028, 5249, 5475, 5706, 5938, 6175, 6417, 6664, 6916, 7173, 7435, 7702, 7974, 8251, 8533, 8820, 9112, 9409, 9711, 10018, 10330, 10647, 10969
Offset: 1

Views

Author

Grady Bullington (bullingt(AT)uwosh.edu), Sep 14 2006

Keywords

Crossrefs

Formula

a(n) = (n-th triangular number)-n+(n-th partial sum of A122798).

A122796 Connell (3,5)-sum sequence (partial sums of the (3,5)-Connell sequence).

Original entry on oeis.org

1, 3, 8, 16, 27, 41, 58, 76, 97, 121, 148, 178, 211, 247, 286, 328, 373, 421, 470, 522, 577, 635, 696, 760, 827, 897, 970, 1046, 1125, 1207, 1292, 1380, 1471, 1565, 1660, 1758, 1859, 1963, 2070, 2180, 2293, 2409, 2528, 2650, 2775, 2903, 3034, 3168, 3305, 3445, 3588, 3734, 3883, 4035, 4190, 4346, 4505, 4667, 4832, 5000, 5171, 5345, 5522, 5702, 5885, 6071, 6260, 6452, 6647, 6845
Offset: 1

Views

Author

Grady Bullington (bullingt(AT)uwosh.edu), Sep 14 2006

Keywords

Crossrefs

Formula

a(n) = (n-th triangular number)-n+(n-th partial sum of A122799).

A045930 The generalized Connell sequence C_{3,5}.

Original entry on oeis.org

1, 2, 5, 8, 11, 14, 17, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 49, 52, 55, 58, 61, 64, 67, 70, 73, 76, 79, 82, 85, 88, 91, 94, 95, 98, 101, 104, 107, 110, 113, 116, 119, 122, 125, 128, 131, 134, 137, 140, 143, 146, 149, 152, 155, 156, 159, 162, 165, 168, 171, 174, 177, 180
Offset: 1

Views

Author

Keywords

Examples

			From _Michel Marcus_, Apr 02 2013: (Start)
As a triangle, sequence begins:
   1;
   2,  5,  8, 11, 14, 17;
  18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48;
  ...
(End)
		

Crossrefs

Cf. A045928.

Programs

Formula

a(n) = 3*n - 2*floor((13 + sqrt(40*n-31))/10). See general formula in A045928. - Michel Marcus, Apr 02 2013

Extensions

More terms from jeroen.lahousse(AT)icl.com

A045929 Generalized Connell sequence C_{5,3}.

Original entry on oeis.org

1, 2, 7, 12, 17, 18, 23, 28, 33, 38, 43, 48, 49, 54, 59, 64, 69, 74, 79, 84, 89, 94, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 156, 161, 166, 171, 176, 181, 186, 191, 196, 201, 206, 211, 216, 221, 226, 231, 232, 237, 242, 247, 252, 257, 262, 267, 272, 277
Offset: 1

Views

Author

Keywords

Examples

			From _Michel Marcus_, Apr 02 2013: (Start)
As a triangle, sequence begins:
   1;
   2,  7, 12, 17;
  18, 23, 28, 33, 38, 43, 48;
  ...
(End)
		

Crossrefs

Cf. A045928.

Programs

  • Mathematica
    Table[5*n - 4*Floor[(7 + Sqrt[24*n - 23])/6],{n,61}] (* Stefano Spezia, Apr 15 2023 *)

Formula

a(n) = 5*n - 4*floor((7 + sqrt(24*n - 23))/6). See general formula in A045928. - Michel Marcus, Apr 02 2013

Extensions

More terms from jeroen.lahousse(AT)icl.com
Showing 1-7 of 7 results.