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.

A257251 Square array A(row,col) = A083221(row,col+1) - A083221(row,col): the first differences of each row of array constructed from the sieve of Eratosthenes.

Original entry on oeis.org

2, 2, 6, 2, 6, 20, 2, 6, 10, 42, 2, 6, 20, 28, 110, 2, 6, 10, 14, 22, 156, 2, 6, 20, 28, 44, 52, 272, 2, 6, 10, 14, 22, 26, 34, 342, 2, 6, 20, 28, 44, 52, 68, 76, 506, 2, 6, 10, 42, 66, 78, 102, 114, 138, 812, 2, 6, 20, 14, 22, 26, 34, 38, 46, 58, 930, 2, 6, 10, 42, 66, 78, 102, 114, 138, 174, 186, 1332
Offset: 1

Views

Author

Antti Karttunen, Apr 19 2015

Keywords

Comments

The array is read by downwards antidiagonals as A(1,1), A(1,2), A(2,1), A(1,3), A(2,2), A(3,1), ...

Examples

			The top left corner of the array:
     2,   2,   2,   2,   2,   2,   2,   2,   2,   2,   2,   2,   2,   2,   2
     6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6
    20,  10,  20,  10,  20,  10,  20,  10,  20,  10,  20,  10,  20,  10,  20
    42,  28,  14,  28,  14,  28,  42,  14,  42,  28,  14,  28,  14,  28,  42
   110,  22,  44,  22,  44,  66,  22,  66,  44,  22,  44,  66,  66,  22,  66
   156,  52,  26,  52,  78,  26,  78,  52,  26,  52,  78,  78,  26,  78,  52
   272,  34,  68, 102,  34, 102,  68,  34,  68, 102, 102,  34, 102,  68,  34
   342,  76, 114,  38, 114,  76,  38,  76, 114, 114,  38, 114,  76,  38, 114
   506, 138,  46, 138,  92,  46,  92, 138, 138,  46, 138,  92,  46, 138,  92
   812,  58, 174, 116,  58, 116, 174, 174,  58, 174, 116,  58, 174, 116, 174
   930, 186, 124,  62, 124, 186, 186,  62, 186, 124,  62, 186, 124, 186, 248
  1332, 148,  74, 148, 222, 222,  74, 222, 148,  74, 222, 148, 222, 296, 148
  1640,  82, 164, 246, 246,  82, 246, 164,  82, 246, 164, 246, 328, 164,  82
  1806, 172, 258, 258,  86, 258, 172,  86, 258, 172, 258, 344, 172,  86, 172
  2162, 282, 282,  94, 282, 188,  94, 282, 188, 282, 376, 188,  94, 188,  94
  2756, 318, 106, 318, 212, 106, 318, 212, 318, 424, 212, 106, 212, 106, 212
  ...
		

Crossrefs

Transpose: A257252.
Column 1: A036689.
Row 4: 7 * A145011.
Cf. A083221, A257253 (same array but with terms divided by 2).
Cf. arrays A257255 and A257257, also A257513.

Programs

Formula

A(row,col) = A083221(row,col+1) - A083221(row,col).
A(row,col) = 2*A257253(row,col).

A257257 Square array A(row,col) = A255127(row,col+1) - A255127(row,col): the first differences of each row of Ludic array.

Original entry on oeis.org

2, 2, 6, 2, 6, 14, 2, 6, 16, 24, 2, 6, 14, 28, 44, 2, 6, 16, 26, 48, 60, 2, 6, 14, 28, 48, 60, 84, 2, 6, 16, 24, 52, 64, 86, 122, 2, 6, 14, 26, 48, 66, 94, 126, 142, 2, 6, 16, 28, 48, 62, 86, 132, 144, 176, 2, 6, 14, 26, 44, 60, 94, 120, 146, 166, 216, 2, 6, 16, 24, 48, 64, 86, 132, 142, 180, 234, 252
Offset: 1

Views

Author

Antti Karttunen, Apr 19 2015

Keywords

Comments

The array A(row,col) is read by downwards antidiagonals as A(1,1), A(1,2), A(2,1), A(1,3), A(2,2), A(3,1), ...

Examples

			The top left corner of the array:
    2,   2,   2,   2,   2,   2,   2,   2,   2,   2,   2,   2,   2,   2,   2
    6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6
   14,  16,  14,  16,  14,  16,  14,  16,  14,  16,  14,  16,  14,  16,  14
   24,  28,  26,  28,  24,  26,  28,  26,  24,  28,  26,  28,  24,  26,  28
   44,  48,  48,  52,  48,  48,  44,  48,  52,  48,  48,  48,  44,  52,  48
   60,  60,  64,  66,  62,  60,  64,  62,  60,  70,  60,  60,  62,  64,  60
   84,  86,  94,  86,  94,  86,  82,  92,  88,  92,  88,  90,  90,  84,  90
  122, 126, 132, 120, 132, 126, 130, 126, 120, 132, 128, 126, 130, 128, 126
  142, 144, 146, 142, 146, 138, 150, 148, 140, 148, 146, 138, 150, 138, 150
  176, 166, 180, 168, 176, 178, 170, 178, 170, 180, 174, 172, 176, 178, 176
  216, 234, 226, 242, 228, 226, 240, 218, 234, 246, 220, 230, 234, 226, 234
  252, 270, 254, 274, 258, 254, 258, 276, 262, 266, 258, 256, 264, 276, 264
  274, 284, 268, 284, 304, 270, 282, 278, 294, 282, 282, 276, 282, 288, 292
  308, 316, 314, 316, 320, 316, 312, 308, 324, 336, 316, 302, 316, 314, 322
  360, 360, 354, 368, 360, 372, 370, 368, 352, 360, 380, 354, 370, 380, 352
  412, 434, 424, 420, 426, 440, 426, 420, 432, 424, 422, 444, 424, 422, 430
  ...
		

Crossrefs

Column 1: A256482.
Cf. A255127.
Cf. A257258 (same array but with terms divided by 2).
Cf. also arrays A257251 and A257255.

Programs

Formula

A(row,col) = A255127(row,col+1) - A255127(row,col).
A(row,col) = 2*A257258(row,col).

A257256 Difference between {the first unlucky number removed at the n-th stage of Lucky sieve} and {the n-th Lucky number}: a(n) = A219178(n) - A000959(n).

Original entry on oeis.org

1, 2, 12, 18, 32, 40, 64, 84, 108, 124, 138, 170, 206, 214, 274, 296, 318, 338, 348, 378, 426, 454, 498, 532, 564, 600, 662, 678, 710, 736, 766, 836, 874, 920, 944, 954, 1078, 1104, 1120, 1170, 1202, 1254, 1296, 1332, 1378, 1416, 1434, 1466, 1592, 1612, 1660, 1696, 1778, 1786, 1820, 1888, 1932, 1952, 2058
Offset: 1

Views

Author

Antti Karttunen, Apr 29 2015

Keywords

Crossrefs

First column of A257255.

Programs

Formula

a(n) = A219178(n) - A000959(n).
Showing 1-3 of 3 results.