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 1-10 of 37 results. Next

A329644 Möbius transform of A323244, the deficiency of A156552(n).

Original entry on oeis.org

0, 1, 1, 1, 1, 2, 1, 4, -1, 3, 1, 5, 1, 14, 0, 0, 1, 9, 1, 12, -5, 16, 1, 8, -5, 44, 4, 5, 1, 2, 1, 24, 12, 80, -4, -4, 1, 254, -14, 0, 1, 22, 1, 47, 7, 224, 1, 24, -13, 19, 6, 83, 1, 12, -21, 44, -14, 746, 1, 14, 1, 1360, 20, -8, 8, 9, 1, 131, 252, 24, 1, 12, 1, 3836, 13, 149, -12, 71, 1, 56, -16, 5456, 1, -21, -74, 12248, -350, -40, 1
Offset: 1

Views

Author

Antti Karttunen, Nov 21 2019

Keywords

Comments

The first eleven zeros occur at n = 1, 15, 16, 40, 96, 119, 120, 160, 893, 2464, 6731. There are 3091 negative terms among the first 10000 terms.
Applying this function to the divisors of the first four terms of A324201 reveals the following pattern:
------------------------------------------------------------------------------------
A324201(n) divisors a(n) applied Sum of positive
to each: terms, A329610
9: [1, 3, 9] -> [0, 1, -1] 1
125: [1, 5, 25, 125] -> [0, 1, -5, 4] 5
161051: [1, 11, 121, 1331, 14641, 161051] -> [0, 1, -29, 4, -240, 264] 269
410338673: [1, 17, 289, 4913, 83521, 1419857, 24137569, 410338673]
-> [0, 1, -125, 4, -1008, 1032, -5048, 5144] 6181
The positive and negative terms seem to alternate, and the fourth term (from case n=125 onward) is always 4. See also array A329637.

Crossrefs

Programs

  • PARI
    A156552(n) = {my(f = factor(n), p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res}; \\ From A156552
    A323244(n) = if(1==n, 0, my(k=A156552(n)); (2*k)-sigma(k));
    A329644(n) = sumdiv(n,d,moebius(n/d)*A323244(d));

Formula

a(n) = Sum_{d|n} A008683(n/d) * A323244(d).
a(n) = Sum_{d|n} A008683(n/d) * (2*A156552(d) - A323243(d)).
a(1) = 0; for n > 1, a(n) = 2*A297112(n) - A324543(n) = 2^A297113(n) - A324543(n).
a(n) = A329642(n) - A329643(n).
For all n >= 1, a(A000040(n)^2) = A323244(A000040(n)^2)-1 = -A036563(n).
For all primes p, a(p^3) = A323244(p^3) - A323244(p^2) = 4.

A329638 Sum of A329644(d) for all such divisors d of n for which that value is positive. Here A329644 is the Möbius transform of A323244, the deficiency of A156552(n).

Original entry on oeis.org

0, 1, 1, 2, 1, 4, 1, 6, 1, 5, 1, 10, 1, 16, 2, 6, 1, 13, 1, 18, 2, 18, 1, 22, 1, 46, 5, 22, 1, 10, 1, 30, 14, 82, 2, 19, 1, 256, 2, 22, 1, 41, 1, 66, 9, 226, 1, 46, 1, 24, 8, 130, 1, 29, 2, 70, 2, 748, 1, 42, 1, 1362, 22, 30, 10, 42, 1, 214, 254, 44, 1, 43, 1, 3838, 15, 406, 2, 120, 1, 78, 5, 5458, 1, 52, 2, 12250, 2, 70, 1, 26, 2, 934
Offset: 1

Views

Author

Antti Karttunen, Nov 21 2019

Keywords

Crossrefs

Programs

  • PARI
    A156552(n) = {my(f = factor(n), p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res}; \\ From A156552
    A323243(n) = if(1==n,0,sigma(A156552(n)));
    A324543(n) = sumdiv(n,d,moebius(n/d)*A323243(d));
    A297113(n) = if(1==n, 0, (primepi(vecmax(factor(n)[, 1])) + (bigomega(n)-omega(n))));
    A329644(n) = if(1==n,0, 2^A297113(n) - A324543(n));
    A329638(n) = sumdiv(n,d,if((d=A329644(d))>0,d,0));

Formula

a(n) = Sum_{d|n} [A329644(d) > 0] * A329644(d), where [ ] is Iverson bracket.
a(n) = A323244(n) + A329639(n).

A329639 Sum of -A329644(d) for all such divisors d of n for which A329644(d) < 0. Here A329644 is the Möbius transform of A323244, the deficiency of A156552(n).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 5, 0, 0, 0, 5, 0, 1, 0, 0, 0, 0, 0, 0, 0, 4, 5, 0, 0, 14, 0, 0, 5, 0, 0, 1, 0, 0, 0, 13, 5, 0, 0, 0, 1, 21, 0, 14, 0, 0, 0, 0, 0, 6, 8, 0, 0, 0, 0, 0, 4, 0, 5, 0, 0, 5, 0, 12, 14, 0, 0, 17, 0, 0, 26, 74, 0, 350, 40, 0, 14, 53, 0, 0, 0, 70, 0, 0, 13, 18, 7, 0, 0, 0, 0, 15
Offset: 1

Views

Author

Antti Karttunen, Nov 21 2019

Keywords

Crossrefs

Programs

Formula

a(n) = -Sum_{d|n} [A329644(d) < 0] * A329644(d), where [ ] is Iverson bracket.
a(n) = A329638(n) - A323244(n).

A324115 a(n) = A002487(A323244(n)).

Original entry on oeis.org

0, 1, 1, 1, 1, 1, 1, 2, 0, 3, 1, 3, 1, 1, 1, 2, 1, 2, 1, 4, -2, 4, 1, 5, -1, 7, 1, 5, 1, 3, 1, 4, 3, 11, -1, 3, 1, 1, -2, 5, 1, 4, 1, 6, 1, 13, 1, 7, -2, 7, 1, 7, 1, 3, -7, 9, -2, 25, 1, 8, 1, 76, 1, 5, 3, 8, 1, 21, 7, 3, 1, 7, 1, 31, 3, 31, -3, 13, 1, 10, -2, 199, 1, 5, -4, 101, -18, 4, 1, 2, -12, 43, 11, 266, -5, 9, 1, 11, -1, 4, 1, 6, 1, 13
Offset: 1

Views

Author

Antti Karttunen, Feb 20 2019

Keywords

Comments

If there are no odd perfect numbers then A324201 gives the positions of all zeros after the initial a(1) = 0.

Crossrefs

Programs

  • PARI
    A002487(n) = if(abs(n)<=1, n, A002487(n\2) + if( n%2, A002487(n\2 + 1))); \\ This version works consistently also with negative arguments, so that a(-n) = -a(n). Except that it is very slow on large n.
    A002487(n) = { my(s=sign(n), a=1, b=0); n = abs(n); while(n>0, if(bitand(n, 1), b+=a, a+=b); n>>=1); (s*b); }; \\ So we use this one, modified from the one given in A002487
    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)};
    A156552(n) = if(1==n, 0, if(!(n%2), 1+(2*A156552(n/2)), 2*A156552(A064989(n))));
    A323244(n) = if(1==n, 0, my(k=A156552(n)); (2*k)-sigma(k));
    A324115(n) = A002487(A323244(n));

Formula

a(n) = A002487(A323244(n)), with the definition of A002487 extended to the negative arguments so that A002487(-n) = -A002487(n).
a(A324201(n)) = 0.

A324551 Positions of negative terms in A323244.

Original entry on oeis.org

21, 25, 35, 39, 49, 55, 57, 77, 81, 85, 87, 91, 95, 99, 105, 111, 115, 121, 129, 133, 143, 155, 159, 161, 169, 183, 185, 187, 189, 195, 201, 203, 205, 209, 213, 221, 225, 235, 237, 247, 253, 259, 265, 267, 285, 287, 289, 295, 299, 301, 303, 319, 321, 323, 325, 335, 339, 341, 343, 351, 355, 361, 365, 371, 377, 381, 385, 391, 393, 403
Offset: 1

Views

Author

Antti Karttunen, Mar 07 2019

Keywords

Comments

Sequence A005940(1+A005101(n)) sorted into ascending order.
The first two even terms are 3710 and 4096, where A323244(3710) = -942 and A323244(4096) = -546.

Crossrefs

A323240 Lexicographically earliest sequence such that for all i, j, a(i) = a(j) => f(i) = f(j), where f(n) = [A001222(n), A323244(n)] for n > 1, and f(1) = 0.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jan 10 2019

Keywords

Comments

Restricted growth sequence transform of function f, where f(1) = 0 and f(n) = [A001222(n), A323244(n)] for n > 1.
Equally, restricted growth sequence transform of function f, where f(1) = 0 and f(n) = A318310(A156552(n)) for n > 1.
For all i, j:
a(i) = a(j) => A323245(i) = A323245(j), [Equally: A323244(i) = A323244(j)]
a(i) = a(j) => A323246(i) = A323246(j). [Equally: A323248(i) = A323248(j)]

Crossrefs

Programs

  • PARI
    up_to = 1024;
    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; };
    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)};
    A156552(n) = if(1==n, 0, if(!(n%2), 1+(2*A156552(n/2)), 2*A156552(A064989(n))));
    A323244(n) = if(1==n, 0, my(k=A156552(n)); (2*k)-sigma(k));
    A323240aux(n) = if(1==n,-1,[bigomega(n),A323244(n)]);
    v323240 = rgs_transform(vector(up_to, n, A323240aux(n)));
    A323240(n) = v323240[n];

A324721 Positions of positive terms in A323244; numbers n for which 2*A156552(n) > A323243(n).

Original entry on oeis.org

2, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 26, 27, 28, 29, 30, 31, 32, 33, 34, 36, 37, 38, 40, 41, 42, 43, 44, 45, 46, 47, 48, 50, 51, 52, 53, 54, 56, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 78, 79, 80, 82, 83, 84, 86, 88, 89, 90, 92, 93, 94, 96, 97, 98, 100
Offset: 1

Views

Author

Antti Karttunen, Mar 12 2019

Keywords

Comments

These correspond to deficient numbers as this is sequence A005940(1+A005100(n)) sorted into ascending order. Subsequence of A324720.

Crossrefs

Cf. A005100, A005940, A156552, A323243, A323244, A324732 (characteristic function).

A329642 a(n) = Sum_{d|n} [1 == A008683(n/d)] * A323244(d), where A323244(x) gives the deficiency of A156552(x).

Original entry on oeis.org

0, 1, 1, 2, 1, 4, 1, 6, 0, 5, 1, 11, 1, 16, 2, 6, 1, 13, 1, 19, -3, 18, 1, 24, -4, 46, 4, 23, 1, 13, 1, 30, 14, 82, -2, 18, 1, 256, -12, 24, 1, 39, 1, 67, 9, 226, 1, 52, -12, 20, 8, 131, 1, 28, -19, 72, -12, 748, 1, 53, 1, 1362, 17, 22, 10, 45, 1, 215, 254, 43, 1, 48, 1, 3838, 11, 407, -10, 109, 1, 84, -12, 5458, 1, 48, -72, 12250, -348, 32, 1, 18
Offset: 1

Views

Author

Antti Karttunen, Nov 21 2019

Keywords

Crossrefs

Cf. A329645 (inverse Möbius transform).

Programs

  • PARI
    A156552(n) = {my(f = factor(n), p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res}; \\ From A156552
    A323243(n) = if(1==n,0,sigma(A156552(n)));
    A329642(n) = sumdiv(n,d,(1==moebius(n/d))*((2*A156552(d))-A323243(d)));

Formula

a(n) = Sum_{d|n} [1 == A008683(n/d)] * (2*A156552(d) - A323243(d)).
a(n) = A329643(n) + A329644(n).

A329643 a(n) = Sum_{d|n} [-1 == A008683(n/d)] * A323244(d), where A323244(x) gives the deficiency of A156552(x).

Original entry on oeis.org

0, 0, 0, 1, 0, 2, 0, 2, 1, 2, 0, 6, 0, 2, 2, 6, 0, 4, 0, 7, 2, 2, 0, 16, 1, 2, 0, 18, 0, 11, 0, 6, 2, 2, 2, 22, 0, 2, 2, 24, 0, 17, 0, 20, 2, 2, 0, 28, 1, 1, 2, 48, 0, 16, 2, 28, 2, 2, 0, 39, 0, 2, -3, 30, 2, 36, 0, 84, 2, 19, 0, 36, 0, 2, -2, 258, 2, 38, 0, 28, 4, 2, 0, 69, 2, 2, 2, 72, 0, 31, 2, 228, 2, 2, 2, 76, 0, 4, 14, 37, 0, 94, 0, 136, -3
Offset: 1

Views

Author

Antti Karttunen, Nov 21 2019

Keywords

Crossrefs

Cf. A329646 (inverse Möbius transform).

Programs

  • PARI
    A156552(n) = {my(f = factor(n), p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res}; \\ From A156552
    A323243(n) = if(1==n,0,sigma(A156552(n)));
    A329643(n) = sumdiv(n,d,(-1==moebius(n/d))*((2*A156552(d))-A323243(d)));

Formula

a(n) = Sum_{d|n} [-1 == A008683(n/d)] * (2*A156552(d) - A323243(d)).
a(n) = A329642(n) - A329644(n).
For all n, a(A000040(n)) = 0, a(A006881(n)) = 2.

A323245 Lexicographically earliest sequence such that for all i, j, a(i) = a(j) => f(i) = f(j), where f(n) = A323244(n) for n > 1, and f(1) = -1.

Original entry on oeis.org

1, 2, 2, 3, 2, 4, 2, 5, 6, 7, 2, 8, 2, 9, 3, 5, 2, 10, 2, 11, 12, 11, 2, 13, 14, 15, 4, 13, 2, 8, 2, 16, 17, 18, 19, 17, 2, 20, 21, 13, 2, 22, 2, 23, 24, 25, 2, 15, 21, 26, 24, 27, 2, 28, 29, 30, 21, 31, 2, 32, 2, 33, 9, 13, 8, 32, 2, 34, 35, 36, 2, 37, 2, 38, 8, 39, 40, 41, 2, 42, 21, 43, 2, 44, 45, 46, 47, 16, 2, 10, 48, 49, 50, 51, 52, 30, 2, 53, 14, 16, 2
Offset: 1

Views

Author

Antti Karttunen, Jan 10 2019

Keywords

Comments

Restricted growth sequence transform of function f, defined as f(1) = -1, and for n > 1, f(n) = A033879(A156552(n)).

Programs

  • PARI
    up_to = 1024;
    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; };
    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)};
    A156552(n) = if(1==n, 0, if(!(n%2), 1+(2*A156552(n/2)), 2*A156552(A064989(n))));
    A323244(n) = if(1==n, 0, my(k=A156552(n)); (2*k)-sigma(k));
    A323245aux(n) = if(1==n,-1,A323244(n));
    v323245 = rgs_transform(vector(up_to, n, A323245aux(n)));
    A323245(n) = v323245[n];
Showing 1-10 of 37 results. Next