A336475 -id:A336475 - cp's OEIS frontend

A336476 a(n) = gcd(A000593(n), A336475(n)).

1, 1, 2, 1, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 12, 1, 2, 1, 2, 2, 4, 2, 2, 2, 1, 2, 4, 2, 2, 12, 2, 1, 12, 2, 4, 1, 2, 2, 4, 2, 2, 4, 2, 2, 6, 2, 2, 2, 3, 1, 12, 2, 2, 4, 4, 2, 4, 2, 2, 12, 2, 2, 2, 1, 4, 12, 2, 2, 12, 4, 2, 1, 2, 2, 2, 2, 4, 4, 2, 2, 1, 2, 2, 4, 4, 2, 12, 2, 2, 6, 28, 2, 4, 2, 20, 2, 2, 3, 6, 1, 2, 12, 2, 2, 24

Offset: 1

Antti Karttunen, Jul 30 2020

nonn

All odd terms k in A001599 (Ore's Harmonic numbers) satisfy a(k) = A336475(k).

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

Cf. A000265, A000593, A001227, A001599, A324121, A336475.

Cf. also A324058, A336320.

A000593(n) = sigma(n>>valuation(n, 2));
A336475(n) = { my(f=factor(n)); prod(i=1, #f~, if(2==f[i,1],1,(1+f[i,2]) * (f[i,1]^f[i,2]))); };
A336476(n) = gcd(A000593(n), A336475(n));

a(n) = gcd(A000593(n), A336475(n)).

a(n) = A324121(A000265(n)).

A336845 a(n) = A000005(n) * A003961(n), where A003961 is the prime shift towards larger primes, and A000005 gives the number of divisors of n, and also of A003961(n).

Original entry on oeis.org

1, 6, 10, 27, 14, 60, 22, 108, 75, 84, 26, 270, 34, 132, 140, 405, 38, 450, 46, 378, 220, 156, 58, 1080, 147, 204, 500, 594, 62, 840, 74, 1458, 260, 228, 308, 2025, 82, 276, 340, 1512, 86, 1320, 94, 702, 1050, 348, 106, 4050, 363, 882, 380, 918, 118, 3000, 364, 2376, 460, 372, 122, 3780, 134, 444, 1650, 5103, 476, 1560

Offset: 1

Antti Karttunen, Aug 06 2020

Dirichlet convolution of A003961 with itself.

Sequence is not injective, as it has duplicate values, for example: a(162) = a(243) = 18750. See also comments in A336475.

Antti Karttunen, Table of n, a(n) for n = 1..16384
Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537
Index entries for sequences computed from indices in prime factorization

Cf. A000005, A000203, A000290, A003961, A038040, A336475.

Cf. also A336841, A336846 [= gcd(a(n),A003973(n))], A336847, A336848.

A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
A336845(n) = (numdiv(n)*A003961(n))

A336845(n) = { my(f = factor(n)); prod(i=1, #f~, (1+f[i,2]) * (nextprime(1+f[i, 1])^f[i,2])); };

A336845(n) = sumdiv(n,d,A003961(d)*A003961(n/d));

Multiplicative with a(prime(i)^e) = (e+1) * prime(1+i)^e.
a(n) = A000005(n) * A003961(n).
a(n) = A038040(A003961(n)).
a(n) = A336841(n) + A003973(n).
a(n) is odd if and only if n is a square.

A347136 a(n) = Sum_{d|n} d * A003961(n/d), where A003961 shifts the prime factorization of its argument one step towards larger primes.

Original entry on oeis.org

1, 5, 8, 19, 12, 40, 18, 65, 49, 60, 24, 152, 30, 90, 96, 211, 36, 245, 42, 228, 144, 120, 52, 520, 109, 150, 272, 342, 60, 480, 68, 665, 192, 180, 216, 931, 78, 210, 240, 780, 84, 720, 90, 456, 588, 260, 100, 1688, 247, 545, 288, 570, 112, 1360, 288, 1170, 336, 300, 120, 1824, 128, 340, 882, 2059, 360, 960, 138

Offset: 1

Antti Karttunen, Aug 24 2021

Dirichlet convolution of the identity function (A000027) with the prime shifted identity (A003961). Multiplicative because both A000027 and A003961 are.
Dirichlet convolution of Euler phi (A000010) with the prime shifted sigma (A003973).
Dirichlet convolution of sigma (A000203) with the prime shifted phi (A003972).
Inverse Möbius transform of A347137.

Antti Karttunen, Table of n, a(n) for n = 1..10000
Index entries for sequences computed from indices in prime factorization

Cf. A003961, A003972, A003973, A151800, A347121, A347137 (Möbius transform).

Cf. also A038040, A336845, A336475, A347236.

f[p_, e_] := ((np = NextPrime[p])^(e + 1) - p^(e + 1))/(np - p); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Aug 24 2021 *)

A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
A347136(n) = sumdiv(n,d,d*A003961(n/d));

a(n) = Sum_{d|n} d * A003961(n/d).
a(n) = Sum_{d|n} A000010(n/d) * A003973(d).
a(n) = Sum_{d|n} A000203(n/d) * A003972(d).
a(n) = Sum_{d|n} A347137(d).
For all primes p, a(p) = p + A003961(p).
a(n) = A347121(n) + 2*n.
Multiplicative with a(p^e) = (A151800(p)^(e+1) - p^(e+1))/(A151800(p)-p). - Amiram Eldar, Aug 24 2021

A336648 Lexicographically earliest infinite sequence such that a(i) = a(j) => A336476(i) = A336476(j), for all i, j >= 1.

Original entry on oeis.org

1, 1, 2, 1, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 3, 1, 2, 1, 2, 2, 4, 2, 2, 2, 1, 2, 4, 2, 2, 3, 2, 1, 3, 2, 4, 1, 2, 2, 4, 2, 2, 4, 2, 2, 5, 2, 2, 2, 6, 1, 3, 2, 2, 4, 4, 2, 4, 2, 2, 3, 2, 2, 2, 1, 4, 3, 2, 2, 3, 4, 2, 1, 2, 2, 2, 2, 4, 4, 2, 2, 1, 2, 2, 4, 4, 2, 3, 2, 2, 5, 7, 2, 4, 2, 8, 2, 2, 6, 5, 1, 2, 3, 2, 2, 9

Offset: 1

Antti Karttunen, Jul 31 2020

nonn

Restricted growth sequence transform of A336476.

For all i, j: A324400(i) = A324400(j) => A003602(i) = A003602(j) => a(i) = a(j).

Antti Karttunen, Table of n, a(n) for n = 1..65537

Cf. A000593, A336475, A336476.

Cf. also A003602, A324400, A336320.

up_to = 65537;
rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
A000593(n) = sigma(n>>valuation(n, 2));
A336475(n) = { my(f=factor(n)); prod(i=1, #f~, if(2==f[i,1],1,(1+f[i,2]) * (f[i,1]^f[i,2]))); };
A336476(n) = gcd(A000593(n), A336475(n));
v336648 = rgs_transform(vector(up_to,n,A336476(n)));
A336648(n) = v336648[n];

cp's OEIS Frontend

A336476 a(n) = gcd(A000593(n), A336475(n)).

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Formula

A336845 a(n) = A000005(n) * A003961(n), where A003961 is the prime shift towards larger primes, and A000005 gives the number of divisors of n, and also of A003961(n).

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Formula

A347136 a(n) = Sum_{d|n} d * A003961(n/d), where A003961 shifts the prime factorization of its argument one step towards larger primes.

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A336648 Lexicographically earliest infinite sequence such that a(i) = a(j) => A336476(i) = A336476(j), for all i, j >= 1.

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