A332703 -id:A332703 - cp's OEIS frontend

A333410 a(n) is the smallest positive integer not yet appearing in the sequence such that n*a(n) contains n as a substring.

1, 6, 10, 11, 3, 16, 21, 23, 22, 31, 100, 26, 87, 51, 41, 73, 69, 66, 63, 36, 58, 101, 97, 52, 5, 102, 103, 46, 79, 61, 107, 76, 192, 151, 81, 38, 201, 89, 164, 35, 59, 34, 173, 126, 99, 184, 74, 135, 153, 7, 167, 176, 29, 251, 121, 28, 168, 148, 27, 56, 92, 123, 137, 57, 141, 207, 25, 113

Offset: 1

Scott R. Shannon, Apr 11 2020

			a(2) = 6 as 6 has not appeared previously and 2 * 6 = 12 which contains '2' as a substring.
a(6) = 16 as 16 has not appeared previously and 6 * 16 = 96 which contains '6' as a substring.
a(7) = 21 as 21 has not appeared previously and 7 * 21 = 147 which contains '7' as a substring.

Scott R. Shannon, Table of n, a(n) for n = 1..10000
Rémy Sigrist, PARI program for A333410

Cf. A086064, A333774, A333775, A333811, A332795, A332703.

PARI
```
See Links section.
```

from itertools import count, islice
def agen(): # generator of terms
    s, mink, aset, concat = 1, 2, {1}, "1"
    yield from [1]
    for n in count(2):
        an, sn = mink, str(n)
        while an in aset or not sn in str(n*an): an += 1
        aset.add(an); s += an; concat += str(an); yield an
        while mink in aset: mink += 1
print(list(islice(agen(), 68))) # Michael S. Branicky, Feb 08 2024

A333774 a(0) = 0; for n > 0, a(n) = the smallest positive integer not yet appearing in the sequence such that a(n-1) + a(n) contains as a substring either a(n-1) or a(n).

Original entry on oeis.org

0, 1, 9, 10, 2, 18, 100, 3, 20, 4, 30, 5, 40, 6, 50, 7, 60, 8, 70, 200, 11, 99, 300, 12, 108, 972, 107, 963, 106, 954, 105, 945, 104, 936, 103, 927, 102, 918, 101, 909, 1000, 13, 117, 1053, 116, 1044, 115, 1035, 114, 1026, 113, 1017, 112, 1008, 111, 999, 110, 990, 109, 981, 2000, 14

Offset: 0

Scott R. Shannon, Apr 05 2020

			a(1) = 1 as a(0) = a(1) = 0 + 1 = 1 which contains '1' as a substring.
a(2) = 9 as a(1) + a(2) = 1 + 9 = 10 which contains '1' as a substring.
a(4) = 2 as a(3) + a(4) = 10 + 2 = 12 which contains '2' as a substring
a(49) = 1026 as a(48) + a(49) = 114 + 1026 = 1140 which contains '114' as a substring.

Rémy Sigrist, Table of n, a(n) for n = 0..10000
Rémy Sigrist, PARI program for A333774

Cf. A333775, A333811, A332795, A332703.

PARI
```
See Links section.
```

A333811 a(0) = 0; for n > 0, a(n) is the smallest positive integer not yet appearing in the sequence such that a(n-1)^a(n) contains as a substring either a(n-1) or a(n).

Original entry on oeis.org

0, 1, 2, 5, 3, 7, 4, 6, 8, 9, 11, 15, 12, 14, 13, 10, 16, 17, 21, 20, 25, 18, 23, 19, 22, 24, 26, 29, 30, 28, 31, 27, 32, 33, 35, 34, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 47, 46, 48, 50, 49, 51, 52, 53, 55, 54, 56, 57, 59, 58, 61, 60, 62, 63, 64, 65, 66, 67, 68, 69, 70

Offset: 0

Scott R. Shannon, Apr 05 2020

a(3) = 5 as a(2) ^ a(3) = 2 ^ 5 = 32 which contains '2' as a substring.
a(4) = 3 as a(3) ^ a(4) = 5 ^ 3 = 125 which contains '5' as a substring.
a(5) = 7 as a(4) ^ a(5) = 3 ^ 7 = 2187 which contains '7' as a substring.

Rémy Sigrist, PARI program for A333811

Cf. A333774, A333775, A332795, A332703.

PARI
```
See Links section.
```

A333775 a(0) = 0; for n > 0, a(n) is the smallest positive integer not yet appearing in the sequence such that a(n-1) * a(n) contains as a substring either a(n-1) or a(n).

Original entry on oeis.org

0, 1, 2, 6, 4, 10, 3, 5, 7, 11, 8, 16, 20, 21, 9, 22, 51, 12, 26, 24, 52, 76, 28, 46, 40, 31, 30, 41, 15, 50, 13, 25, 17, 69, 34, 42, 94, 100, 14, 82, 71, 60, 36, 38, 89, 55, 61, 35, 80, 56, 87, 33, 75, 29, 53, 101, 18, 66, 151, 32, 91, 43, 102, 19, 63, 137, 83, 96, 126, 44, 59, 27, 103

Offset: 0

Scott R. Shannon, Apr 05 2020

			a(1) = 1 as a(0) * a(1) = 0 * 1 = 0 which contains '0' as a substring.
a(4) = 4 as a(3) * a(4) = 6 * 4 = 24 which contains '4' as a substring.
a(18) = 26 as a(17) * a(18) = 12 * 26 = 312 which contains '12' as a substring.

Rémy Sigrist, Table of n, a(n) for n = 0..10000
Rémy Sigrist, PARI program for A333775

Cf. A333774, A333811, A332795, A332703.

PARI
```
See Links section.
```

A341035 a(n) is the smallest positive integer such that n+a(n) contains the string n-a(n), in both forward and reverse directions, as a substring. If no such number exists then a(n) = -1.

Original entry on oeis.org

-1, -1, -1, -1, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 10, 10, 10, 10, 10, 15, 15, 15, 15, 15, 20, 20, 20, 20, 20, 25, 25, 25, 25, 25, 29, 30, 30, 30, 30, 33, 34, 35, 35, 35, 37, 38, 39, 40, 40, 41, 42, 43, 44, 45, 50, 50, 50, 50, 50, 55, 50, 51, 52, 53, 54, 60, 60, 60, 60, 65, 50, 50, 65, 65, 70, 70, 70

Offset: 1

Scott R. Shannon, Feb 03 2021

Based on a search limit of 5*10^9 up to n = 300000 the values of n for which no a(n) is found are n = 1,2,3,4. This is likely the complete list of values for which no a(n) exists.

The longest run of consecutive terms with the same value in the first 300000 terms is the run of 5's at the beginning of the sequence, ten in all. This is likely the longest run for all numbers.

			a(5) = 5 as 5+5 = 10 which contains both 5-5 = 0 and reverse(0) = 0 as a substring.
a(15) = 10 as 15+10 = 25 which contains both 15-10 = 5 and reverse(5) = 5 as a substring.
a(61) = 50 as 61+50 = 111 which contains both 51-50 = 11 and reverse(11) = 11 as a substring.
a(71) = 50 as 71+50 = 121 which contains both 71-50 = 21 and reverse(21) = 12 as a substring.
a(1902) = 1829 as 1902+1829 = 3731 which contains both 1902-1829 = 73 and reverse(73) = 37 as a substring.

Scott R. Shannon, Image of the terms for n=5..100000.

Cf. A341034 (forward), A341028 (reverse), A339403, A339144, A328095, A333410, A332703.

A333923 a(n) is the smallest positive integer such that n^a(n) is divisible by n+a(n).

Original entry on oeis.org

2, 6, 4, 20, 3, 42, 8, 18, 6, 110, 4, 156, 14, 10, 16, 272, 6, 342, 5, 6, 10, 506, 3, 100, 6, 54, 4, 812, 6, 930, 32, 48, 30, 14, 12, 1332, 26, 42, 10, 1640, 6, 1806, 20, 30, 18, 2162, 6, 294, 14, 30, 12, 2756, 10, 66, 8, 24, 6, 3422, 4, 3660, 62, 18, 64, 60, 6, 4422

Offset: 2

Scott R. Shannon, Apr 10 2020

nonn

As in A063427, if n is a prime then a(n^k) = (n-1)*n^k for k>=1. This sequence also matches A063427 for numerous other nonprime terms for small values of n.

For n below 10000 the values where n = a(n), other than n being a power of 2, are n = 14, 62, 122, 254, 508, 1018, 2038, 2042, 8182, 8186.

			a(2) = 2 as 2 ^ 2 = 4 is divisible by 2 + 2 = 4.
a(3) = 6 as 3 ^ 6 = 729 is divisible by 3 + 6 = 9.
a(4) = 4 as 4 ^ 4 = 256 is divisible by 4 + 4 = 8.
a(5) = 20 as 5 ^ 20 = 95367431640625 is divisible by 5 + 20 = 25.

Harvey P. Dale, Table of n, a(n) for n = 2..1000

Cf. A063427, A333811, A332795, A332703.

spi[n_]:=Module[{k=1},While[PowerMod[n,k,n+k]!=0,k++];k]; Array[spi,70,2] (* Harvey P. Dale, Jan 16 2022 *)

A341028 a(n) is the smallest positive integer such that n+a(n) contains the string n-a(n) in reverse as a substring. If no such number exists then a(n) = -1.

Original entry on oeis.org

-1, -1, -1, -1, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 10, 10, 10, 10, 10, 15, 15, 9, 15, 15, 20, 20, 20, 20, 20, 25, 25, 25, 9, 25, 29, 30, 30, 30, 30, 33, 34, 35, 35, 9, 37, 38, 39, 40, 40, 41, 42, 43, 44, 45, 9, 50, 50, 50, 50, 55, 41, 51, 52, 53, 54, 9, 60, 60, 60, 65, 50, 32, 52, 53, 54, 70, 9

Offset: 1

Scott R. Shannon, Feb 02 2021

Based on a search limit of 5*10^9 up to n = 300000 the values of n for which no a(n) is found are n = 1,2,3,4. This is likely the complete list of values for which a(n) = -1.
The longest run of consecutive terms with the same value in the first 300000 terms is the run of 5's at the beginning of the sequence, ten in all. This is likely the longest run for all numbers.
Numerous patterns exist in the values of a(n), e.g., when a(n) consists of all 9's and n is not a power of 10 then n is palindromic.

			a(5) = 5 as 5+5 = 10 which contains reverse(5-5) = reverse(0) = 0 as a substring.
a(6) = 5 as 6+5 = 11 which contains reverse(6-5) = reverse(1) = 1 as a substring.
a(15) = 10 as 15+10 = 25 which contains reverse(15-10) = reverse(5) = 5 as a substring.
a(22) = 9 as 22+9 = 31 which contains reverse(22-9) = reverse(13) = 31 as a substring.

Scott R. Shannon, Image of the terms for n = 5..300000. It is possible the frame-like pattern continues to larger and larger scales resulting in a fractal structure.

Cf. A341034 (forward), A341035 (forward and reverse), A339403, A339144, A328095, A333410, A332703.

A341034 a(n) is the smallest positive integer such that n+a(n) contains the string n-a(n) as a substring. If no such number exists then a(n) = -1.

Original entry on oeis.org

-1, -1, -1, -1, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 10, 10, 10, 10, 10, 15, 15, 15, 15, 15, 20, 20, 20, 20, 20, 25, 25, 25, 25, 25, 29, 30, 30, 30, 30, 33, 34, 35, 35, 35, 37, 38, 39, 40, 40, 41, 42, 43, 44, 45, 45, 46, 47, 48, 49, 50, 50, 50, 50, 50, 50, 50, 50, 50, 50, 50, 50, 50, 50, 50, 50, 50, 50

Offset: 1

Scott R. Shannon, Feb 03 2021

Based on a search limit of 5*10^9 up to n = 200000 the values of n for which no a(n) is found are n = 1,2,3,4. This is likely the complete list of values for which no a(n) exists.

The sequence contains long runs of consecutive terms with the same value, resulting in the image for the values having a staircase-like pattern. In the first 200000 terms the longest run is 88890 terms, starting from a(61110), all of which have a(n) = 50000.

			a(5) = 5 as 5+5 = 10 which contains 5-5 = 0 as a substring.
a(6) = 5 as 6+5 = 11 which contains 6-5 = 1 as a substring.
a(15) = 10 as 15+10 = 25 which contains 15-10 = 5 as a substring.
a(35) = 29 as 35+29 = 64 which contains 35-29 = 6 as a substring.

Scott R. Shannon, Line graph of the terms for n=5..6111.

Cf. A341028 (reverse), A341035 (forward and reverse), A339403, A339144, A328095, A333410, A332703.

cp's OEIS Frontend

A333410 a(n) is the smallest positive integer not yet appearing in the sequence such that n*a(n) contains n as a substring.

Views

Author

Keywords

Examples

Links

Crossrefs

Programs

PARI

Python

A333774 a(0) = 0; for n > 0, a(n) = the smallest positive integer not yet appearing in the sequence such that a(n-1) + a(n) contains as a substring either a(n-1) or a(n).

Views

Author

Keywords

Examples

Links

Crossrefs

Programs

PARI

A333811 a(0) = 0; for n > 0, a(n) is the smallest positive integer not yet appearing in the sequence such that a(n-1)^a(n) contains as a substring either a(n-1) or a(n).

Views

Author

Keywords

Comments

Links

Crossrefs

Programs

PARI

A333775 a(0) = 0; for n > 0, a(n) is the smallest positive integer not yet appearing in the sequence such that a(n-1) * a(n) contains as a substring either a(n-1) or a(n).

Views

Author

Keywords

Examples

Links

Crossrefs

Programs

PARI

A341035 a(n) is the smallest positive integer such that n+a(n) contains the string n-a(n), in both forward and reverse directions, as a substring. If no such number exists then a(n) = -1.

Views

Author

Keywords

Comments

Examples

Links

Crossrefs

A333923 a(n) is the smallest positive integer such that n^a(n) is divisible by n+a(n).

Views

Author

Keywords

Comments

Examples

Links

Crossrefs

Programs

Mathematica

A341028 a(n) is the smallest positive integer such that n+a(n) contains the string n-a(n) in reverse as a substring. If no such number exists then a(n) = -1.

Views

Author

Keywords

Comments

Examples

Links

Crossrefs

A341034 a(n) is the smallest positive integer such that n+a(n) contains the string n-a(n) as a substring. If no such number exists then a(n) = -1.

Views

Author

Keywords

Comments

Examples

Links

Crossrefs