A342456 -id:A342456 - cp's OEIS frontend

A342463 a(n) = A342001(A342456(n)); "wild part" of the arithmetic derivative of A342456(n).

1, 1, 1, 2, 1, 2, 12, 8, 1, 2, 6, 4, 50, 24, 16, 16, 1, 2, 6, 4, 126, 62, 46, 26, 1486, 100, 1142, 48, 2056, 32, 342, 10, 1, 2, 6, 4, 94, 24, 72, 18, 242, 120, 1588, 54, 3408, 92, 1740, 22, 6846, 2972, 4340, 766, 5048, 1374, 652, 376, 71156, 22710, 20390, 64, 738580, 4272, 568, 20, 1, 2, 6, 4, 264, 12, 196, 8, 318

Offset: 0

Antti Karttunen, Mar 15 2021

Like in A342462, also here the subsequences starting at each n = 2^k seem to be slowly converging towards A329886: 1, 2, 6, 4, 30, 12, 36, 8, 210, 60, ...

Cf. A003415, A003557, A005940, A108951, A329886, A342001, A342002, A342456, A342462, A342920.

Block[{a, f, r = MixedRadix[Reverse@ Prime@ Range@ 24]}, f[n_] := Times @@ MapIndexed[Prime[First[#2]]^#1 &, Reverse@ IntegerDigits[n, r]]; a[0] = 1; a[1] = 2; a[n_] := a[n] = If[EvenQ@ n, (Times @@ Map[Prime[PrimePi@ #1 + 1]^#2 & @@ # &, FactorInteger[#]] - Boole[# == 1])*2^IntegerExponent[#, 2] &[a[n/2]], 2 a[(n - 1)/2]]; Array[#1/#2 & @@ {If[# < 2, 0, # Total[#2/#1 & @@@ FactorInteger[#]]] &@ Abs[#], #/Times @@ FactorInteger[#][[All, 1]]} &@ f@ a[#] &, 73, 0]] (* Michael De Vlieger, Mar 17 2021 *)

\\ Needs also code from A342456.
A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
A003557(n) = (n/factorback(factorint(n)[, 1]));
A342001(n) = (A003415(n) / A003557(n));
A342463(n) = A342001(A342456(n));

a(n) = A342001(A342456(n)) = A342002(A329886(n)) = A342920(A005940(1+n)).

A342457 Terms of A342456 prime-shifted so far towards lower primes that they become even: a(n) = 2*A246277(A342456(n)).

Original entry on oeis.org

2, 2, 2, 4, 2, 4, 6, 6, 2, 4, 64, 16, 324, 36, 10, 36, 2, 4, 64, 16, 2304, 96, 486, 24, 7290, 104976, 21600, 1296, 1708593750000, 100, 93750, 10, 2, 4, 64, 16, 144, 6, 216, 6, 172186884, 7776, 2160, 216, 216000000, 236196, 10497600, 54, 10935000000000, 53144100, 1476225000000, 7290, 122500000000, 10935000, 140, 360

Offset: 0

Antti Karttunen, Mar 15 2021

nonn

These terms have the same prime signature as the corresponding terms in A342456, thus applying omega and bigomega to these gives the same derived sequences A342461 and A342462.

Cf. A246277, A276086, A283980, A329038, A329886, A342456, A342461 [= A001221(a(n))], A342462 [= A001222(a(n))], A342464 [= A051903(a(n))].

A246277(n) = if(1==n, 0, my(f = factor(n), k = primepi(f[1,1])-1); for (i=1, #f~, f[i,1] = prime(primepi(f[i,1])-k)); factorback(f)/2);
A342457(n) = 2*A246277(A342456(n)); \\ Uses also code from A342456.

a(n) = 2*A246277(A342456(n)) = 2*A329038(A329886(n)).

A342001 Arithmetic derivative without its inherited divisor; the arithmetic derivative of n divided by A003557(n), which is a common divisor of both n and A003415(n).

Original entry on oeis.org

0, 1, 1, 2, 1, 5, 1, 3, 2, 7, 1, 8, 1, 9, 8, 4, 1, 7, 1, 12, 10, 13, 1, 11, 2, 15, 3, 16, 1, 31, 1, 5, 14, 19, 12, 10, 1, 21, 16, 17, 1, 41, 1, 24, 13, 25, 1, 14, 2, 9, 20, 28, 1, 9, 16, 23, 22, 31, 1, 46, 1, 33, 17, 6, 18, 61, 1, 36, 26, 59, 1, 13, 1, 39, 11, 40, 18, 71, 1, 22, 4, 43, 1, 62, 22, 45, 32, 35, 1, 41, 20

Offset: 1

Antti Karttunen, Feb 28 2021

nonn

See also the scatter plot of A342002 that seems to reveal some interesting internal structure in this sequence, not fully explained by the regularity of primorial base expansion used in the latter sequence. - Antti Karttunen, May 09 2022

Antti Karttunen, Table of n, a(n) for n = 1..16384
Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537

Cf. A003415, A003557, A341998, A342416, A342459.
Cf. A342002 [= a(A276086(n))], A342463 [= a(A342456(n))], A351945 [= a(A181819(n))], A353571 [= a(A003961(n))].
Cf. A346485 (Möbius transform), A347395 (convolution with Liouville's lambda), A347961 (with itself), and A347234, A347235, A347954, A347959, A347963, A349396, A349612 (for convolutions with other sequences).
Cf. A007947.

Array[#1/#2 & @@ {If[# < 2, 0, # Total[#2/#1 & @@@ FactorInteger[#]]] &@ Abs[#], #/Times @@ FactorInteger[#][[All, 1]]} &, 91] (* Michael De Vlieger, Mar 11 2021 *)

A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
A003557(n) = (n/factorback(factorint(n)[, 1]));
A342001(n) = (A003415(n) / A003557(n));

from math import prod
from sympy import factorint
def A342001(n):
    q = prod(f:=factorint(n))
    return sum(q*e//p for p, e in f.items()) # Chai Wah Wu, Nov 04 2022

a(n) = A003415(n) / A003557(n).
For all n >= 0, a(A276086(n)) = A342002(n).
a(n) = A342414(n) * A342416(n) = A342459(n) * A342919(n). - Antti Karttunen, Apr 30 2022
Dirichlet g.f.: Dirichlet g.f. of A007947 * Sum_{p prime} p^s/((p^s-1)*(p^s+p-1)) = zeta(s) * Product_{p prime} (1+p^(1-s)-p^(-s)) * Sum_{p prime} p^s/((p^s-1)*(p^s+p-1)). - Sebastian Karlsson, May 05 2022
Sum_{k=1..n} a(k) ~ c * A065464 * Pi^2 * n^2 / 12, where c = Sum_{j>=2} (1/2 + (-1)^j * (Fibonacci(j) - 1/2))*PrimeZetaP(j) = 0.4526952873143153104685540856936425315834753528741817723313791528384... - Vaclav Kotesovec, May 09 2022

A342462 Sum of digits when A329886(n) is written in primorial base, where A329886 is the primorial inflation of Doudna-tree.

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 2, 2, 1, 2, 6, 4, 6, 4, 2, 4, 1, 2, 6, 4, 10, 6, 6, 4, 8, 12, 10, 8, 22, 4, 8, 2, 1, 2, 6, 4, 6, 2, 6, 2, 18, 10, 8, 6, 18, 12, 16, 4, 26, 16, 24, 8, 20, 14, 4, 6, 26, 16, 14, 8, 30, 6, 8, 4, 1, 2, 6, 4, 14, 12, 12, 8, 18, 12, 24, 4, 8, 12, 14, 4, 24, 20, 28, 20, 26, 16, 16, 12, 32, 26, 24, 14, 28, 16

Offset: 0

Antti Karttunen, Mar 15 2021

nonn

From David A. Corneth's Feb 27 2019 comment in A276150 follows that the only odd terms in this sequence are 1's occurring at 0 and at two's powers.

Subsequences starting at each n = 2^k are slowly converging towards A329886: 1, 2, 6, 4, 30, 12, 36, 8, 210, 60, 180, 24, etc.. Compare also to the behaviors of A324342 and A342463.

Antti Karttunen, Table of n, a(n) for n = 0..8192
Antti Karttunen, Data supplement: n, a(n) computed for n = 0..65537
Index entries for sequences related to binary expansion of n
Index entries for sequences related to primorial base

Cf. A001222, A005940, A108951, A276150, A329886, A342456, A342457, A342461, A342463, A342464.

Cf. also A324342, A324383, A324387, A324888.

A342462(n) = bigomega(A342456(n)); \\ Other code as in A342456.

A283980(n) = {my(f=factor(n)); prod(i=1, #f~, my(p=f[i, 1], e=f[i, 2]); if(p==2, 6, nextprime(p+1))^e)};
A329886(n) = if(n<2,1+n,if(!(n%2),A283980(A329886(n/2)),2*A329886(n\2)));
A276150(n) = { my(s=0, p=2, d); while(n, d = (n%p); s += d; n = (n-d)/p; p = nextprime(1+p)); (s); };
A342462(n) = A276150(A329886(n));

a(n) = A001222(A342456(n)) = A001222(A342457(n)).
a(n) = A276150(A329886(n)) = A324888(A005940(1+n)).
a(n) >= A342461(n).
For n >= 0, a(2^n) = 1.

A342461 Number of nonzero digits when A329886(n) is written in primorial base, where A329886 is the primorial inflation of Doudna-tree.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 3, 2, 3, 2, 3, 2, 3, 2, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 2, 3, 2, 3, 2, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 2, 5, 4, 3, 2, 1, 1, 1, 1, 2, 1, 2, 1, 2, 2, 2, 2, 3, 2, 3, 2, 3, 3, 3, 2, 4, 3, 3, 2, 4, 3, 4, 3, 4, 3, 4, 2, 3, 4, 4, 3, 4, 3, 4, 3, 3, 4

Offset: 0

Antti Karttunen, Mar 15 2021

nonn

Cf. A001221, A005940, A108951, A267263, A329886, A342456, A342457, A342462.

Cf. also A324341, A329040.

A342461(n) = omega(A342456(n)); \\ Other code as in A342456.

a(n) = A001221(A342456(n)) = A001221(A342457(n)).
a(n) = A267263(A329886(n)) = A329040(A005940(1+n)).
a(n) <= A342462(n).
For n >= 0, a(2^n) = 1.

A342464 Largest digit value when A329886(n) is written in primorial base, where A329886 is the primorial inflation of Doudna-tree.

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 1, 1, 1, 2, 6, 4, 4, 2, 1, 2, 1, 2, 6, 4, 8, 5, 5, 3, 6, 8, 5, 4, 11, 2, 6, 1, 1, 2, 6, 4, 4, 1, 3, 1, 16, 5, 4, 3, 9, 10, 8, 3, 10, 12, 10, 6, 10, 7, 2, 3, 18, 10, 5, 4, 12, 2, 4, 2, 1, 2, 6, 4, 13, 12, 10, 8, 12, 8, 13, 2, 4, 6, 7, 2, 15, 15, 12, 10, 9, 8, 7, 6, 10, 12, 10, 9, 11, 6, 9, 6, 18, 15

Offset: 0

Antti Karttunen, Mar 15 2021

nonn

Cf. A005940, A051903, A108951, A276086, A328114, A329344, A329886, A342456, A342461, A342462.

A283980(n) = {my(f=factor(n)); prod(i=1, #f~, my(p=f[i, 1], e=f[i, 2]); if(p==2, 6, nextprime(p+1))^e)}; \\ From A283980
A329886(n) = if(n<2,1+n,if(!(n%2),A283980(A329886(n/2)),2*A329886(n\2)));
A328114(n) = { my(s=0, p=2); while(n, s = max(s,(n%p)); n = n\p; p = nextprime(1+p)); (s); };
A342464(n) = A328114(A329886(n));

a(n) = A328114(A329886(n)) = A051903(A342456(n)) = A329344(A005940(1+n)).

cp's OEIS Frontend

A342463 a(n) = A342001(A342456(n)); "wild part" of the arithmetic derivative of A342456(n).

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A342457 Terms of A342456 prime-shifted so far towards lower primes that they become even: a(n) = 2*A246277(A342456(n)).

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A342001 Arithmetic derivative without its inherited divisor; the arithmetic derivative of n divided by A003557(n), which is a common divisor of both n and A003415(n).

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A342462 Sum of digits when A329886(n) is written in primorial base, where A329886 is the primorial inflation of Doudna-tree.

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A342461 Number of nonzero digits when A329886(n) is written in primorial base, where A329886 is the primorial inflation of Doudna-tree.

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A342464 Largest digit value when A329886(n) is written in primorial base, where A329886 is the primorial inflation of Doudna-tree.

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