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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A334103 Numbers n for which A329697(n) == 3.

Original entry on oeis.org

19, 21, 23, 27, 29, 31, 33, 35, 37, 38, 39, 42, 45, 46, 53, 54, 55, 58, 61, 62, 65, 66, 70, 73, 74, 75, 76, 78, 83, 84, 89, 90, 92, 101, 103, 106, 108, 110, 113, 116, 119, 122, 123, 124, 125, 130, 132, 140, 146, 148, 150, 152, 153, 156, 166, 168, 178, 180, 184, 187, 202, 205, 206, 212, 216, 220, 221, 226, 232, 238, 241, 244
Offset: 1

Views

Author

Antti Karttunen, Apr 14 2020

Keywords

Comments

Numbers n for which A171462(n) = n-A052126(n) is in A334102.
Among the first 2821 terms (terms < 2^31), there are terms with binary weights 2, 3, 4, 5, 6 and 8. For example, 33 is the first term with binary weight 2, and 255 is the first term with binary weight 8.

Crossrefs

Row 3 of A334100.
Cf. A334093 (primes present), A334094.

Programs

A334104 Numbers m for which A329697(m) = 4.

Original entry on oeis.org

43, 47, 49, 57, 59, 63, 67, 69, 71, 77, 79, 81, 86, 87, 91, 93, 94, 95, 98, 99, 105, 107, 109, 111, 114, 115, 117, 118, 121, 126, 131, 134, 135, 138, 142, 143, 145, 149, 151, 154, 155, 157, 158, 159, 162, 165, 167, 169, 172, 174, 175, 179, 181, 182, 183, 185, 186, 188, 190, 195, 196, 198, 210, 214, 218, 219, 222, 225
Offset: 1

Views

Author

Antti Karttunen, Apr 14 2020

Keywords

Comments

Squares of A334102 form a subsequence.
Among the first 12193 terms (terms < 2^31), there are terms with binary weights 2 - 16, except no terms with weight 13, 14 or 15. For example, 1025 is the first term with binary weight 2, and 65535 is the first term with binary weight 16.

Examples

			63 = 7*9 is a term as both 7 and 9 are terms of A334102.
65535 = 3*5*17*257 is a term as it is a product of four Fermat primes, thus in four steps all odd primes can be eliminated with p -> (p-1) map.
		

Crossrefs

Row 4 of A334100.
Cf. A334094 (primes present).

Programs

  • Mathematica
    Position[Array[Length@NestWhileList[# - #/FactorInteger[#][[-1, 1]] &, #, # != 2^IntegerExponent[#, 2] &] - 1 &, 225], 4][[All, 1]] (* Michael De Vlieger, Apr 30 2020 *)
  • PARI
    A329697(n) = if(!bitand(n,n-1),0,1+A329697(n-(n/vecmax(factor(n)[, 1]))));
    isA334104(n) = (4==A329697(n));

A333794 a(1) = 1, for n > 1, a(n) = n + a(n-A052126(n)).

Original entry on oeis.org

1, 3, 6, 7, 12, 13, 20, 15, 22, 25, 36, 27, 40, 41, 42, 31, 48, 45, 64, 51, 66, 73, 96, 55, 76, 81, 72, 83, 112, 85, 116, 63, 118, 97, 120, 91, 128, 129, 130, 103, 144, 133, 176, 147, 136, 193, 240, 111, 182, 153, 162, 163, 216, 145, 208, 167, 202, 225, 284, 171, 232, 233, 208, 127, 236, 237, 304, 195, 306, 241, 312, 183, 256, 257
Offset: 1

Views

Author

Antti Karttunen, Apr 05 2020

Keywords

Comments

Conjecturally, also the largest path sum when iterating from n to 1 with nondeterministic map k -> k - k/p, where p is any prime factor of k.

Examples

			For n=119, the graph obtained is this:
              119
             _/\_
            /    \
          102    112
         _/|\_    | \_
       _/  |  \_  |   \_
      /    |    \ |     \
    51     68    96     56
    /|   _/ |   _/|   _/ |
   / | _/   | _/  | _/   |
  /  |/     |/    |/     |
(48) 34    64     48    28
     |\_    |    _/|   _/|
     |  \_  |  _/  | _/  |
     |    \_|_/    |/    |
    17     32     24    14
      \_    |    _/|   _/|
        \_  |  _/  | _/  |
          \_|_/    |/    |
           16      12    7
            |    _/|    _/
            |  _/  |  _/
            |_/    |_/
            8     _6
            |  __/ |
            |_/    |
            4      3
             \     /
              \_ _/
                2
                |
                1.
If we always subtract A052126(n) (i.e., n divided by its largest prime divisor), i.e., iterate with A171462 (starting from 119), we obtain 119-(119/17) = 112 -> 112-(112/7) -> 96-(96/3) -> 64-(64/2) -> 32-(32/2) -> 16-(16/2) -> 8-(8/2) -> 4-(4/2) -> 2-(2/2) -> 1, with sum 119+112+96+64+32+16+8+4+2+1 = 554, thus a(119) = 554. This happens also to be maximal sum of any path in above diagram.
		

Crossrefs

Programs

  • Mathematica
    Array[Total@ NestWhileList[# - #/FactorInteger[#][[-1, 1]] &, #, # > 1 &] &, 74] (* Michael De Vlieger, Apr 14 2020 *)
  • PARI
    A333794(n) = if(1==n,n,n + A333794(n-(n/vecmax(factor(n)[, 1]))));

Formula

a(1) = 1; and for n > 1, a(n) = n + a(A171462(n)) = n + a(n-A052126(n)).
a(n) = A073934(n) + A333793(n).
a(n) = n + Max a(n - n/p), for p prime and dividing n. [Conjectured, holds at least up to n=2^24]
For all n >= 1, A333790(n) <= a(n) <= A332904(n).
For all n >= 1, a(n) >= A332993(n). [Apparently, have to check!]

A334094 Primes p for which A329697(p) == 4.

Original entry on oeis.org

43, 47, 59, 67, 71, 79, 107, 109, 131, 149, 151, 157, 167, 179, 181, 227, 233, 239, 251, 281, 293, 307, 313, 337, 433, 443, 521, 593, 601, 613, 673, 809, 821, 823, 881, 929, 953, 971, 977, 1021, 1201, 1217, 1249, 1637, 1697, 1931, 2081, 2113, 2309, 2657, 2689, 2741, 2789, 2819, 3203, 3209, 3299, 3457, 3469, 3593, 3617, 3847, 3881, 4001
Offset: 1

Views

Author

Antti Karttunen, Apr 14 2020

Keywords

Comments

Primes p of the form of the form A334103(n) + 1, for some n >= 1.

Crossrefs

Programs

A334106 Numbers n for which A329697(n) == 6.

Original entry on oeis.org

283, 301, 329, 343, 347, 361, 379, 381, 383, 387, 399, 413, 417, 419, 423, 431, 437, 441, 463, 469, 473, 483, 487, 489, 491, 497, 509, 513, 517, 519, 523, 529, 531, 539, 547, 551, 553, 557, 559, 566, 567, 571, 573, 589, 591, 597, 599, 602, 603, 609, 611, 621, 627, 631, 633, 635, 637, 639, 643, 645, 649, 651, 653, 658, 665
Offset: 1

Views

Author

Antti Karttunen, Apr 14 2020

Keywords

Crossrefs

Row 6 of A334100.
Cf. A334096 (primes present).

Programs

A335904 Fully additive with a(2) = 0, and a(p) = 1+a(p-1)+a(p+1), for odd primes p.

Original entry on oeis.org

0, 0, 1, 0, 2, 1, 2, 0, 2, 2, 4, 1, 4, 2, 3, 0, 3, 2, 5, 2, 3, 4, 6, 1, 4, 4, 3, 2, 6, 3, 4, 0, 5, 3, 4, 2, 8, 5, 5, 2, 6, 3, 8, 4, 4, 6, 8, 1, 4, 4, 4, 4, 8, 3, 6, 2, 6, 6, 10, 3, 8, 4, 4, 0, 6, 5, 9, 3, 7, 4, 7, 2, 11, 8, 5, 5, 6, 5, 8, 2, 4, 6, 10, 3, 5, 8, 7, 4, 9, 4, 6, 6, 5, 8, 7, 1, 6, 4, 6, 4, 9, 4, 9, 4, 5
Offset: 1

Views

Author

Antti Karttunen, Jun 29 2020

Keywords

Crossrefs

Programs

  • PARI
    A335904(n) = { my(f=factor(n)); sum(k=1,#f~,if(2==f[k,1],0,f[k,2]*(1+A335904(f[k,1]-1)+A335904(f[k,1]+1)))); };

Formula

Totally additive with a(2) = 0, and for odd primes p, a(p) = 1 + a(p-1) + a(p+1).
a(n) = A336118(n) + A087436(n).
For all n >= 1, a(A335915(n)) = A336118(n).
For all n >= 1, a(n) >= A335884(n) >= A335881(n) >= A335875(n) >= A335885(n).
For all n >= 0, a(3^n) = n.

A334095 Primes p for which A329697(p) == 5.

Original entry on oeis.org

127, 139, 163, 173, 191, 197, 199, 211, 223, 229, 263, 269, 271, 277, 311, 317, 331, 349, 359, 367, 373, 397, 421, 439, 457, 461, 467, 479, 499, 503, 541, 563, 569, 587, 607, 617, 619, 647, 661, 677, 701, 733, 739, 751, 761, 857, 877, 887, 919, 937, 997, 1009, 1031, 1049, 1061, 1069, 1123, 1187, 1193, 1213, 1229, 1231
Offset: 1

Views

Author

Antti Karttunen, Apr 14 2020

Keywords

Comments

Primes p of the form of the form A334104(n) + 1, for some n >= 1.

Crossrefs

Programs

A334096 Primes p for which A329697(p) == 6.

Original entry on oeis.org

283, 347, 379, 383, 419, 431, 463, 487, 491, 509, 523, 547, 557, 571, 599, 631, 643, 653, 683, 691, 709, 719, 727, 743, 757, 787, 797, 811, 829, 853, 859, 907, 911, 941, 991, 1013, 1033, 1051, 1087, 1091, 1093, 1109, 1117, 1129, 1151, 1163, 1171, 1181, 1277, 1289, 1381, 1399, 1451, 1453, 1493, 1511, 1523, 1559, 1571, 1583, 1607
Offset: 1

Views

Author

Antti Karttunen, Apr 14 2020

Keywords

Comments

Primes p of the form of the form A334105(n) + 1, for some n >= 1.

Crossrefs

Programs

A334105 Numbers m for which A329697(m) = 5.

Original entry on oeis.org

127, 129, 133, 139, 141, 147, 161, 163, 171, 173, 177, 189, 191, 197, 199, 201, 203, 207, 209, 211, 213, 215, 217, 223, 229, 231, 235, 237, 243, 245, 247, 253, 254, 258, 259, 261, 263, 266, 269, 271, 273, 277, 278, 279, 282, 285, 294, 295, 297, 299, 311, 315, 317, 319, 321, 322, 326, 327, 331, 333, 335, 341, 342, 345, 346, 349, 351
Offset: 1

Views

Author

Antti Karttunen, Apr 14 2020

Keywords

Examples

			127 = 63*2 + 1 is a term, as 127 is a prime and 63 is in A334104 as A329697(63) = 4.
2^32 -1 = 4294967295 = 3*5*17*257*65537 is a term as it is a product of five Fermat primes, thus in five steps all odd primes can be eliminated with p -> (p-1) map.
Likewise for 1442840405 = 5 * 17 * 257^3. (The first term with binary weight = 24).
		

Crossrefs

Row 5 of A334100.
Cf. A334095 (primes present).

Programs

  • Mathematica
    Position[Array[Length@ NestWhileList[# - #/FactorInteger[#][[-1, 1]] &, #, # != 2^IntegerExponent[#, 2] &] - 1 &, 360], 5][[All, 1]] (* Michael De Vlieger, Apr 30 2020 *)
  • PARI
    A329697(n) = if(!bitand(n,n-1),0,1+A329697(n-(n/vecmax(factor(n)[, 1]))));
    isA334105(n) = (5==A329697(n));

A335876 a(1) = 2, and for n > 1, a(n) = n + (n/p), where p is largest prime dividing n, A006530(n).

Original entry on oeis.org

2, 3, 4, 6, 6, 8, 8, 12, 12, 12, 12, 16, 14, 16, 18, 24, 18, 24, 20, 24, 24, 24, 24, 32, 30, 28, 36, 32, 30, 36, 32, 48, 36, 36, 40, 48, 38, 40, 42, 48, 42, 48, 44, 48, 54, 48, 48, 64, 56, 60, 54, 56, 54, 72, 60, 64, 60, 60, 60, 72, 62, 64, 72, 96, 70, 72, 68, 72, 72, 80, 72, 96, 74, 76, 90, 80, 84, 84, 80, 96, 108, 84, 84
Offset: 1

Views

Author

Antti Karttunen, Jun 28 2020

Keywords

Crossrefs

Cf. A006530, A052126, A171462, A331410, A334097, A335431 (positions of two's powers > 2).

Programs

  • Mathematica
    Array[# (1 + 1/FactorInteger[#][[-1, 1]]) &, 83] (* Michael De Vlieger, Jul 08 2020 *)
  • PARI
    A335876(n) = if(1==n,2,n + (n/vecmax(factor(n)[, 1])));

Formula

a(n) = n + A052126(n).
Previous Showing 11-20 of 25 results. Next