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.

A346108 a(n) = A276085(A108951(A346096(n))), where A346096(n) gives the numerator of the primorial deflation of A276086(A108951(n)).

Original entry on oeis.org

1, 3, 9, 6, 39, 18, 249, 9, 39, 78, 2559, 36, 32589, 498, 234, 18, 543099, 78, 10242789, 156, 1494, 5118, 233335659, 57, 996, 65178, 258, 996, 6703028889, 405, 207263519019, 42, 15354, 1086198, 6612, 156, 7628001653829, 20485578, 195534, 249, 311878265181039, 2559, 13394639596851069, 10236, 1245, 466671318, 628284422185342479
Offset: 1

Views

Author

Antti Karttunen, Jul 08 2021

Keywords

Crossrefs

Programs

Formula

a(n) = A108951(n) + A346109(n).

A346098 a(n) = A064989(A346096(n)) = A064989(A319626(A324886(n))).

Original entry on oeis.org

1, 2, 3, 4, 5, 9, 7, 3, 5, 25, 11, 81, 13, 49, 15625, 9, 17, 25, 19, 625, 117649, 121, 23, 45, 2401, 169, 21, 2401, 29, 4375, 31, 10, 1771561, 289, 14235529, 625, 37, 361, 4826809, 7, 41, 11, 43, 14641, 16807, 529, 47, 125, 2093663, 5764801, 24137569, 28561, 53, 441, 20449, 5764801, 47045881, 841, 59, 343, 61, 961, 1331, 100, 396067447082177
Offset: 1

Views

Author

Antti Karttunen, Jul 07 2021

Keywords

Crossrefs

Cf. A064989, A319626, A324886, A346095, A346096, A346097, A346099 [= gcd(n, a(n))].

Programs

Formula

A346106 a(n) = A108951(A346096(n)), where A346096(n) gives the numerator of the primorial deflation of A276086(A108951(n)).

Original entry on oeis.org

2, 6, 30, 36, 210, 900, 2310, 30, 210, 44100, 30030, 810000, 510510, 5336100, 85766121000000, 900, 9699690, 44100, 223092870, 1944810000, 151939915084881000000, 901800900, 6469693230, 189000, 28473963210000, 260620460100, 69300, 28473963210000, 200560490130, 4492511100000, 7420738134810, 1260, 733384949590939374729000000
Offset: 1

Views

Author

Antti Karttunen, Jul 08 2021

Keywords

Crossrefs

Programs

Formula

a(n) = A324886(n) * A346107(n).

A346097 Denominator of the primorial deflation of A276086(A108951(n)): a(n) = A319627(A324886(n)).

Original entry on oeis.org

1, 2, 3, 4, 5, 9, 7, 2, 3, 25, 11, 81, 13, 49, 15625, 4, 17, 9, 19, 625, 117649, 121, 23, 27, 1225, 169, 21, 2401, 29, 3125, 31, 10, 1771561, 289, 5764801, 81, 37, 361, 4826809, 5, 41, 7, 43, 14641, 12005, 529, 47, 75, 1127357, 1500625, 24137569, 28561, 53, 441, 14641, 5764801, 47045881, 841, 59, 125, 61, 961, 343, 100, 302875106592253
Offset: 1

Views

Author

Antti Karttunen, Jul 07 2021

Keywords

Comments

Denominator of ratio A324886(n) / A329044(n).

Crossrefs

Cf. A346096 (numerators).
Cf. also A337377.

Programs

Formula

a(n) = A319627(A324886(n)).
a(n) = A329044(n) / A346095(n) = A329044(n) / gcd(A324886(n), A329044(n)).
A020639(a(n)) = A006530(n).
A108951(a(n)) = A346107(n).
A346105(a(n)) = A346109(n).

A337376 Primorial deflation (numerator) of Doudna-tree.

Original entry on oeis.org

1, 2, 3, 4, 5, 3, 9, 8, 7, 10, 5, 6, 25, 9, 27, 16, 11, 14, 21, 20, 7, 5, 15, 12, 49, 50, 25, 9, 125, 27, 81, 32, 13, 22, 33, 28, 55, 21, 63, 40, 11, 14, 7, 10, 35, 15, 45, 24, 121, 98, 147, 100, 49, 25, 25, 18, 343, 250, 125, 27, 625, 81, 243, 64, 17, 26, 39, 44, 65, 33, 99, 56, 91, 110, 55, 42, 275, 63, 189, 80, 13, 22
Offset: 0

Views

Author

Keywords

Comments

Tree with both numerators (this sequence) and denominators (A337377) shown starts as:
1/1
|
2
-
1
3 / \ 4
- ................. ................. -
2 1
5 / \ 3 9 / \ 8
- ....... ....... - - ....... ....... -
3 1 4 1
/ \ / \ / \ / \
/ \ / \ / \ / \
/ \ / \ / \ / \
7 10 5 6 25 9 27 16
- -- - - -- - -- --
5 3 2 1 9 2 8 1
/ \ / \ / \ / \ / \ / \ / \ / \
11 14 21 20 7 5 15 12 49 50 25 9 125 27 81 32
-- -- -- -- - - -- -- -- -- -- - --- -- -- --
7 5 10 3 3 1 4 1 25 9 6 1 27 4 16 1
etc.

Crossrefs

A005940, A319626, A337375 are used in a formula defining this sequence.
Cf. A064989.
Cf. A337377 (denominators).
A000265, A001222, A003961, A007814, A337821 are used to express relationship between terms of this sequence.
Cf. also A329886, A346096.

Programs

  • Mathematica
    Array[#1/GCD[#1, #2] & @@ {#, Apply[Times, Map[If[#1 <= 2, 1, NextPrime[#1, -1]]^#2 & @@ # &, FactorInteger[#]]]} &@ Function[p, Times @@ Flatten@ Table[Prime[Count[Flatten[#], 0] + 1]^#[[1, 1]] &@ Take[p, -i], {i, Length[p]}]]@ Partition[Split[Join[IntegerDigits[# - 1, 2], {2}]], 2] &, 82] (* Michael De Vlieger, Aug 27 2020 *)
  • PARI
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); (t); };
    A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
    A319626(n) = (n / gcd(n, A064989(n)));
    A337376(n) = A319626(A005940(1+n));

Formula

a(n) = A319626(A005940(1+n)).
a(n) = A005940(1+n) / A337375(n).
a(2*n) = A003961(a(n)).
If A007814(n+1) < A337821(n+1) then a(2*n+1) = a(n), otherwise a(2*n+1) = 2 * a(n).
If A337377(n) mod 2 = 0 then a(2*n+1) = a(n), otherwise a(2*n+1) = 2 * a(n).
A000265(a(2*n+1)) = A000265(a(n)).
A001222(a(2*n)) = A001222(A337377(2*n)) = A001222(a(n)).
A001222(a(2*n+1)) - A001222(A337377(2*n+1)) = 1 + A001222(a(n)) - A001222(A337377(n)).

A346095 a(n) = gcd(A324886(n), A064989(A324886(n))).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 3, 5, 1, 1, 1, 1, 1, 1, 9, 1, 25, 1, 1, 1, 1, 1, 5, 49, 1, 1, 1, 1, 7, 1, 1, 1, 1, 121, 625, 1, 1, 1, 7, 1, 11, 1, 1, 7, 1, 1, 5, 143, 2401, 1, 1, 1, 1, 169, 1, 1, 1, 1, 343, 1, 1, 1331, 1, 17, 1, 1, 1, 1, 161051, 1, 175, 1, 1, 41503, 1, 169, 1, 1, 49, 35, 1, 1, 121, 19, 1, 1, 1, 1, 49, 24137569
Offset: 1

Views

Author

Antti Karttunen, Jul 07 2021

Keywords

Crossrefs

Programs

  • PARI
    A330749(n) = {my(f); f = factor(n); if((n>1 && f[1, 1]==2), f[1, 2] = 0); for (i=1, #f~, f[i, 1] = precprime(f[i, 1]-1)); gcd(n, factorback(f)); };
    A346095(n) = A330749(A324886(n)); \\ Rest of program given in A324886.

Formula

a(n) = A330749(A324886(n)) = gcd(A324886(n), A329044(n)) = gcd(A324886(n), A064989(A324886(n))).
a(n) = A324886(n) / A346096(n).
a(n) = A329044(n) / A346097(n).
a(n) mod A006530(n) > 0, for all n > 1.

A346099 a(n) = gcd(n, A346098(n)).

Original entry on oeis.org

1, 2, 3, 4, 5, 3, 7, 1, 1, 5, 11, 3, 13, 7, 5, 1, 17, 1, 19, 5, 7, 11, 23, 3, 1, 13, 3, 7, 29, 5, 31, 2, 11, 17, 7, 1, 37, 19, 13, 1, 41, 1, 43, 11, 1, 23, 47, 1, 1, 1, 17, 13, 53, 9, 11, 7, 19, 29, 59, 1, 61, 31, 1, 4, 13, 11, 67, 17, 23, 1, 71, 3, 73, 37, 25, 19, 1, 13, 79, 1, 1, 41, 83, 1, 17, 43, 29, 11, 89
Offset: 1

Views

Author

Antti Karttunen, Jul 07 2021

Keywords

Comments

Only powers of primes (A000961) occur as terms. A346100 lists the exponents.

Crossrefs

Cf. A346090 (positions of ones).

Programs

Formula

a(n) = gcd(n, A346098(n)) = gcd(n, A064989(A319626(A324886(n)))).

A346100 a(n) = A100995(gcd(n, A064989(A319626(A324886(n))))).

Original entry on oeis.org

0, 1, 1, 2, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 1, 1, 2, 1, 1, 1, 1, 1, 0, 1, 1, 0, 2, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 2, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 3
Offset: 1

Views

Author

Antti Karttunen, Jul 07 2021

Keywords

Crossrefs

Programs

  • PARI
    A064989(n) = { my(f = factor(n)); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f); };
    A319626(n) = (n / gcd(n, A064989(n)));
    A346100(n) = isprimepower(gcd(n, A064989(A319626(A324886(n))))); \\ Rest of program given in A324886.

Formula

a(n) = A100995(A346099(n)) = A100995(gcd(n, A064989(A319626(A324886(n))))).
Showing 1-8 of 8 results.