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 1-8 of 8 results.

A036326 Composite numbers n such that juxtaposition of prime factors of n has length 2.

Original entry on oeis.org

4, 6, 9, 10, 14, 15, 21, 25, 35, 49
Offset: 1

Views

Author

Patrick De Geest, Dec 15 1998

Keywords

Comments

There are exactly 10 such numbers.

Crossrefs

Cf. A036327-A036334, A046368.

A036327 Composite numbers n such that juxtaposition of prime factors of n has length 3.

Original entry on oeis.org

8, 12, 18, 20, 22, 26, 27, 28, 30, 33, 34, 38, 39, 42, 45, 46, 50, 51, 55, 57, 58, 62, 63, 65, 69, 70, 74, 75, 77, 82, 85, 86, 87, 91, 93, 94, 95, 98, 105, 106, 111, 115, 118, 119, 122, 123, 125, 129, 133, 134, 141, 142, 145, 146, 147, 155, 158, 159, 161, 166, 175
Offset: 1

Views

Author

Patrick De Geest, Dec 15 1998

Keywords

Comments

The last term is a(104)=679.

Links

Crossrefs

Cf. A036326-A036334.

Programs

  • Maple
    isA036327 := proc(n) local d: d:=ifactors(n)[2]: return `if`(not isprime(n) and add(length(d[j][1])*d[j][2], j=1..nops(d))=3, n, NULL): end: seq(isA036327(n),n=2..999); # Nathaniel Johnston, Jun 22 2011

A036333 Composite numbers n such that juxtaposition of prime factors of n has length 9.

Original entry on oeis.org

512, 768, 1152, 1280, 1408, 1664, 1728, 1792, 1920, 2112, 2176, 2432, 2496, 2592, 2688, 2880, 2944, 3168, 3200, 3264, 3520, 3648, 3712, 3744, 3872, 3888, 3968, 4032, 4160, 4320, 4416, 4480, 4576, 4736, 4752, 4800, 4896, 4928, 5248, 5280, 5408, 5440
Offset: 1

Views

Author

Patrick De Geest, Dec 15 1998

Keywords

Comments

The last term is a(84018465) = 997210243 = 9973 * 99991. - Giovanni Resta, Mar 21 2013
Prime factors counted with multiplicity. - Harvey P. Dale, Jul 26 2017

Links

Crossrefs

Cf. A036326-A036334.

Programs

  • Maple
    isA036333 := proc(n) local d: d:=ifactors(n)[2]: return `if`(not isprime(n) and add(length(d[j][1])*d[j][2], j=1..nops(d))=9, n, NULL): end: seq(isA036333(n),n=2..5440); # Nathaniel Johnston, Jun 22 2011
  • Mathematica
    jpf9Q[n_]:=CompositeQ[n]&&Total[IntegerLength[#[[1]]]#[[2]]&/@ FactorInteger[ n]]==9; Select[ Range[6000],jpf9Q] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 26 2017 *)

A036328 Composite numbers n such that juxtaposition of prime factors of n has length 4.

Original entry on oeis.org

16, 24, 36, 40, 44, 52, 54, 56, 60, 66, 68, 76, 78, 81, 84, 90, 92, 99, 100, 102, 110, 114, 116, 117, 121, 124, 126, 130, 135, 138, 140, 143, 148, 150, 153, 154, 164, 165, 169, 170, 171, 172, 174, 182, 186, 187, 188, 189, 190, 195, 196, 202, 206, 207, 209, 210
Offset: 1

Views

Author

Patrick De Geest, Dec 15 1998

Keywords

Comments

The last term of this sequence is a(1048)=9409.
Prime factors are taken with multiplicity. - Harvey P. Dale, Dec 05 2015

Links

Crossrefs

Cf. A036326-A036334.

Programs

  • Maple
    isA036328 := proc(n) local d: d:=ifactors(n)[2]: return `if`(not isprime(n) and add(length(d[j][1])*d[j][2], j=1..nops(d))=4, n, NULL): end: l:=[seq(isA036328(n),n=2..9999)]; # Nathaniel Johnston, Jun 22 2011
  • Mathematica
    jpf4Q[n_]:=Length[Flatten[IntegerDigits/@Table[#[[1]],{#[[2]]}]&/@FactorInteger[n]]]==4; Select[Range[300],jpf4Q] (* Harvey P. Dale, Dec 05 2015 *)

A036329 Composite numbers n such that juxtaposition of prime factors of n has length 5.

Original entry on oeis.org

32, 48, 72, 80, 88, 104, 108, 112, 120, 132, 136, 152, 156, 162, 168, 180, 184, 198, 200, 204, 220, 228, 232, 234, 242, 243, 248, 252, 260, 270, 276, 280, 286, 296, 297, 300, 306, 308, 328, 330, 338, 340, 342, 344, 348, 351, 363, 364, 372, 374, 376, 378
Offset: 1

Views

Author

Patrick De Geest, Dec 15 1998

Keywords

Comments

The last term of this sequence is a(10077) = 96709.

Links

Crossrefs

Cf. A036326-A036334.

Programs

  • Maple
    isA036329 := proc(n) local d: d:=ifactors(n)[2]: return `if`(not isprime(n) and add(length(d[j][1])*d[j][2], j=1..nops(d))=5, n, NULL): end: l:=[seq(isA036329(n),n=2..378)]; # Nathaniel Johnston, Jun 22 2011
  • Mathematica
    jpf5Q[n_]:=Total[Flatten[Table[IntegerLength[#[[1]]],{#[[2]]}]&/@ FactorInteger[ n]]]==5; Select[Range[400],CompositeQ[#]&&jpf5Q[#]&] (* Harvey P. Dale, Jan 09 2015 *)

A036330 Composite numbers n such that juxtaposition of prime factors of n has length 6.

Original entry on oeis.org

64, 96, 144, 160, 176, 208, 216, 224, 240, 264, 272, 304, 312, 324, 336, 360, 368, 396, 400, 408, 440, 456, 464, 468, 484, 486, 496, 504, 520, 540, 552, 560, 572, 592, 594, 600, 612, 616, 656, 660, 676, 680, 684, 688, 696, 702, 726, 728, 729, 744, 748, 752
Offset: 1

Views

Author

Patrick De Geest, Dec 15 1998

Keywords

Comments

The last term of this sequence is a(96411)=994009.

Links

Crossrefs

Cf. A036326-A036334.

Programs

  • Maple
    isA036330 := proc(n) local d: d:=ifactors(n)[2]: return `if`(not isprime(n) and add(length(d[j][1])*d[j][2], j=1..nops(d))=6, n, NULL): end: seq(isA036330(n),n=2..752); # Nathaniel Johnston, Jun 22 2011
  • Mathematica
    pf6Q[n_]:=!PrimeQ[n]&&Total[Last[#]IntegerLength[First[#]]&/@FactorInteger[ n]]==6; Select[Range[800],pf6Q]  (* Harvey P. Dale, Jun 19 2012 *)

A036331 Composite numbers n such that juxtaposition of prime factors of n has length 7.

Original entry on oeis.org

128, 192, 288, 320, 352, 416, 432, 448, 480, 528, 544, 608, 624, 648, 672, 720, 736, 792, 800, 816, 880, 912, 928, 936, 968, 972, 992, 1008, 1040, 1080, 1104, 1120, 1144, 1184, 1188, 1200, 1224, 1232, 1312, 1320, 1352, 1360, 1368, 1376, 1392, 1404, 1452
Offset: 1

Views

Author

Patrick De Geest, Dec 15 1998

Keywords

Comments

The last term of this sequence is a(919196)=9943081.

Links

Crossrefs

Cf. A036326-A036334.

Programs

  • Maple
    isA036331 := proc(n) local d: d:=ifactors(n)[2]: return `if`(not isprime(n) and add(length(d[j][1])*d[j][2], j=1..nops(d))=7, n, NULL): end: seq(isA036331(n),n=2..1452); # Nathaniel Johnston, Jun 22 2011

A036332 Composite numbers n such that juxtaposition of prime factors of n has length 8.

Original entry on oeis.org

256, 384, 576, 640, 704, 832, 864, 896, 960, 1056, 1088, 1216, 1248, 1296, 1344, 1440, 1472, 1584, 1600, 1632, 1760, 1824, 1856, 1872, 1936, 1944, 1984, 2016, 2080, 2160, 2208, 2240, 2288, 2368, 2376, 2400, 2448, 2464, 2624, 2640, 2704, 2720, 2736
Offset: 1

Views

Author

Patrick De Geest, Dec 15 1998

Keywords

Comments

The last term of this sequence is a(8779116)=99691027.

Links

Crossrefs

Cf. A036326-A036334.

Programs

  • Maple
    isA036332 := proc(n) local d: d:=ifactors(n)[2]: return `if`(not isprime(n) and add(length(d[j][1])*d[j][2], j=1..nops(d))=8, n, NULL): end: seq(isA036332(n),n=2..2736); # Nathaniel Johnston, Jun 22 2011
Showing 1-8 of 8 results.

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