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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A284273 Main diagonal of A284270.

Original entry on oeis.org

0, 0, 0, 0, 2, 0, 0, 0, 2, 8, 8, 0, 12, 0, 0, 0, 2, 8, 11, 12, 16, 10, 3, 0, 9, 22, 18, 0, 12, 0, 0, 0, 2, 8, 30, 32, 11, 6, 26, 8, 19, 22, 0, 40, 1, 12, 37, 0, 17, 36, 18, 36, 7, 18, 16, 0, 27, 48, 13, 0, 12, 0, 0, 0, 2, 8, 30, 32, 53, 50, 40, 56, 32, 44, 2, 24, 73, 26, 61, 32, 14, 76, 28, 4, 34, 0, 64, 72, 86, 4, 73, 48, 16, 54, 11, 0, 33
Offset: 1

Views

Author

Antti Karttunen, Apr 10 2017

Keywords

Crossrefs

Programs

Formula

a(n) = A277699(n) mod n = A048720(n, A065621(n)) mod n.

A277199 Transpose of square array A277320.

Original entry on oeis.org

1, 2, 2, 7, 4, 3, 4, 14, 6, 4, 13, 8, 9, 8, 5, 14, 26, 12, 28, 10, 6, 11, 28, 23, 16, 27, 12, 7, 8, 22, 18, 52, 20, 18, 14, 8, 25, 16, 29, 56, 57, 24, 21, 16, 9, 26, 50, 24, 44, 54, 46, 28, 56, 18, 10, 31, 52, 43, 32, 39, 36, 35, 32, 63, 20, 11, 28, 62, 46, 100, 40, 58, 42, 104, 36, 54, 22, 12, 21, 56, 33, 104, 125, 48, 49, 112, 101, 40, 49, 24, 13
Offset: 1

Views

Author

Antti Karttunen, Nov 01 2016

Keywords

Comments

See A277320.

Examples

			The top left corner of the array:
   1,  2,  7,  4,  13,  14,  11,   8,  25,  26,  31,  28
   2,  4, 14,  8,  26,  28,  22,  16,  50,  52,  62,  56
   3,  6,  9, 12,  23,  18,  29,  24,  43,  46,  33,  36
   4,  8, 28, 16,  52,  56,  44,  32, 100, 104, 124, 112
   5, 10, 27, 20,  57,  54,  39,  40, 125, 114,  99, 108
   6, 12, 18, 24,  46,  36,  58,  48,  86,  92,  66,  72
   7, 14, 21, 28,  35,  42,  49,  56,  79,  70,  93,  84
   8, 16, 56, 32, 104, 112,  88,  64, 200, 208, 248, 224
   9, 18, 63, 36, 101, 126,  83,  72, 209, 202, 231, 252
  10, 20, 54, 40, 114, 108,  78,  80, 250, 228, 198, 216
  11, 22, 49, 44, 127,  98,  69,  88, 227, 254, 217, 196
  12, 24, 36, 48,  92,  72, 116,  96, 172, 184, 132, 144
		

Crossrefs

Transpose: A277320.
Main diagonal: A277699.
Row 1: A065621, Row 3: 3: A277823.
Column 1: A000027, Column 3: A048727.
Cf. A048720.

Programs

Formula

A(r,c) = A048720(r, A065621(c)).

A309573 a(n) is the sum of lattice points enumerated by the square number spiral falling on the circumference of circles centered at the origin of radii n.

Original entry on oeis.org

0, 16, 64, 144, 256, 912, 576, 784, 1024, 1296, 3648, 1936, 2304, 7312, 3136, 8208, 4096, 11824, 5184, 5776, 14592, 7056, 7744, 8464, 9216, 41232, 29248, 11664, 12544, 27568, 32832, 15376, 16384, 17424, 47296, 44688, 20736, 61104, 23104, 65808, 58368, 78096, 28224, 29584, 30976, 73872
Offset: 0

Views

Author

Torlach Rush, Aug 08 2019

Keywords

Comments

For this sequence the square spiral begins with 0 and is the second illustration in the comments of A317186, where 0 is the origin of our circles.
a(n) >= A001107(n) + A033991(n) + A007742(n) + A033954(n).
a(n) = A016802(n) iff A046109(n) = 4.
a(n) = A016802(n) iff n <> k * A002144(m), k,m >= 1.
a(n) is congruent to 0 mod 16 and is the sum of one or more terms of A016802.
Conjecture: a(n) is a term of A277699 iff a(n)/16 = A277699(n).

Examples

			16 is a term because 16 = 16*(1)^2.
912 is a term because 912 = 16*(5)^2 + (2*(16*(4)^2)).
41232 is a term because 41232 = 16*(25)^2 + (2*((16*(24)^2) + (16*(20)^2))).
		

Crossrefs

Programs

  • PARI
    Tb(n) = {return(16 * n * n)}
    llsum(n) = {my(x=0); for (i = 1, n - 2, for (ii = i+1, n - 1, if(n*n == (ii*ii) + (i*i), x+=(2 * Tb(ii))))); return(x)}
    Tx(n) = {my(x=0); forprimestep(x = 5, n, 4, if(n%x==0, return(llsum(n))))}
    Tn(n) = {for (i = 0, n, print1(Tb(i) + Tx(i), ", "))}
    Tn(45)
Previous Showing 11-13 of 13 results.