A295887 -id:A295887 - cp's OEIS frontend

A322587 Lexicographically earliest such sequence a that for all i, j, a(i) = a(j) => f(i) = f(j), where f(n) = 0 for odd primes, and f(n) = A291756(n) [equally: A295887(n)] for any other number.

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

Offset: 1

Antti Karttunen, Dec 18 2018

nonn

For all i, j: a(i) = a(j) => A322320(i) = A322320(j).

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

Cf. A291756, A295887, A322588, A322589, A322591, A322592.

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; };
A003557(n) = { my(f=factor(n)); for(i=1, #f~, f[i, 2] = f[i, 2]-1); factorback(f); };
A173557(n) = my(f=factor(n)[, 1]); prod(k=1, #f, f[k]-1); \\ From A173557
Aux322587(n) = if((n>2)&&isprime(n),0,(1/2)*(2 + ((A003557(n)+A173557(n))^2) - A003557(n) - 3*A173557(n)));
v322587 = rgs_transform(vector(up_to, n, Aux322587(n)));
A322587(n) = v322587[n];

A291751 Lexicographically earliest such sequence a that a(i) = a(j) => A003557(i) = A003557(j) and A048250(i) = A048250(j), for all i, j.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 6, 11, 12, 13, 13, 14, 10, 15, 16, 17, 18, 19, 13, 20, 21, 22, 23, 24, 25, 26, 18, 27, 28, 29, 28, 30, 31, 32, 33, 34, 22, 35, 36, 37, 38, 26, 28, 39, 40, 41, 26, 42, 29, 43, 26, 44, 45, 46, 32, 47, 48, 35, 49, 50, 51, 52, 53, 54, 35, 52, 26, 55, 56, 57, 58, 59, 35, 60, 45, 61, 62, 63, 51, 64, 65, 66, 67, 68, 46, 69, 70, 47, 71

Offset: 1

Antti Karttunen, Sep 06 2017

nonn

Restricted growth sequence transform of A291750, which means that this is the lexicographically least sequence a, such that for all i, j: a(i) = a(j) <=> A291750(i) = A291750(j) <=> A003557(i) = A003557(j) and A048250(i) = A048250(j). That this is equal to the definition given in the title follows because any such lexicographically least sequence satisfying relation <=> is also the least sequence satisfying relation => with the same parameters.

Sigma (A000203) and psi (A001615) are functions of this sequence. See comments in A291750 for the reason. For example, to find the value of A001615(n) when we know just a(n), but without knowing n, let m be the least i for which a(i) = a(n); then A001615(n) = A003991(A291750(m)) = A003557(m) * A048250(m).

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

Cf. A001615, A003557, A048250, A291750, A291752, A294877, A295300, A295886, A295887, A295888, A319698, A322021.

Differs from A286603 for the first time at n = 25, where a(25) = 21, while A286603(25) = 14.

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; };
A003557(n) = n/factorback(factor(n)[, 1]); \\ From A003557
A048250(n) = if(n<1, 0, sumdiv(n, d, if(core(d)==d, d)));
A291750(n) = (1/2)*(2 + ((A003557(n)+A048250(n))^2) - A003557(n) - 3*A048250(n));
v291751 = rgs_transform(vector(65537,n,A291750(n)));
A291751(n) = v291751[n];

Name changed and comments added by Antti Karttunen, Nov 24 2018

A295886 Filter-sequence combining A003557(n) and A023900(n).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 21, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 34, 38, 39, 13, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 54, 71, 72, 73, 67, 74, 75, 76, 52, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 73

Offset: 1

Antti Karttunen, Dec 03 2017

nonn

For all i, j: a(i) = a(j) => A295887(i) = A295887(j).

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

Cf. A003557, A023900, A295876, A295887.

allocatemem(2^30);
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; };
write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
A003557(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 2] = max(0,f[i, 2]-1)); factorback(f); };
A023900(n) = sumdivmult(n, d, d*moebius(d)); \\ This function from Charles R Greathouse IV, Sep 09 2014
v295876 = rgs_transform(vector(up_to,n,A023900(n)))
A295876(n) = v295876[n];
Anotsubmitted6(n) = (1/2)*(2 + ((A003557(n)+A295876(n))^2) - A003557(n) - 3*A295876(n));
write_to_bfile(1,rgs_transform(vector(up_to,n,Anotsubmitted6(n))),"b295886.txt");

Restricted growth sequence transform of sequence a(n) = (1/2)*(2 + ((A003557(n) + A295876(n))^2) - A003557(n) - 3*A295876(n)).

A295888 Filter combining prime signature of n (A101296) with Dedekind's psi (A001615).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 14, 15, 16, 17, 18, 17, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 31, 33, 34, 35, 36, 37, 38, 39, 40, 41, 41, 42, 43, 44, 45, 46, 42, 47, 48, 49, 42, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 56, 60, 63, 64, 65, 66, 67, 67, 56, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 77

Offset: 1

Antti Karttunen, Dec 03 2017

nonn

Antti Karttunen, Table of n, a(n) for n = 1..65537
Eric Weisstein's World of Mathematics, Pairing Function
Wikipedia, Pairing Function

Cf. A001615, A046523, A101296, A291750, A295300, A295880, A295887, A296090.

allocatemem(2^30);
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; };
write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
A001615(n) = (n * sumdivmult(n, d, issquarefree(d)/d)); \\ This function from Charles R Greathouse IV, Sep 09 2014
A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ This function from Charles R Greathouse IV, Aug 17 2011
Anotsubmitted8(n) = (1/2)*(2 + ((A046523(n)+A001615(n))^2) - A046523(n) - 3*A001615(n));
write_to_bfile(1,rgs_transform(vector(up_to,n,Anotsubmitted8(n))),"b295888.txt");

Restricted growth sequence transform of function f(n) = (1/2)*(2 + ((A046523(n) + A001615(n))^2) - A046523(n) - 3*A001615(n)), where values A046523(n) and A001615(n) are packed together to a(n) with the 2-argument form of A000027, also known as Cantor pairing-function.

A322809 Lexicographically earliest such sequence a that a(i) = a(j) => f(i) = f(j) for all i, j, where f(n) = -1 if n is an odd prime, and f(n) = floor(n/2) for all other numbers.

Original entry on oeis.org

1, 2, 3, 4, 3, 5, 3, 6, 6, 7, 3, 8, 3, 9, 9, 10, 3, 11, 3, 12, 12, 13, 3, 14, 14, 15, 15, 16, 3, 17, 3, 18, 18, 19, 19, 20, 3, 21, 21, 22, 3, 23, 3, 24, 24, 25, 3, 26, 26, 27, 27, 28, 3, 29, 29, 30, 30, 31, 3, 32, 3, 33, 33, 34, 34, 35, 3, 36, 36, 37, 3, 38, 3, 39, 39, 40, 40, 41, 3, 42, 42, 43, 3, 44, 44, 45, 45, 46, 3, 47, 47, 48, 48, 49, 49, 50, 3, 51, 51, 52, 3, 53, 3, 54, 54

Offset: 1

Antti Karttunen, Dec 26 2018

nonn

This sequence is a restricted growth sequence transform of a function f which is defined as f(n) = A004526(n), unless n is an odd prime, in which case f(n) = -1, which is a constant not in range of A004526. See the Crossrefs section for a list of similar sequences.
For all i, j:
  A305801(i) = A305801(j) => a(i) = a(j),
  a(i) = a(j) => A039636(i) = A039636(j).
For all i, j: a(i) = a(j) <=> A323161(i+1) = A323161(j+1).
The shifted version of this filter, A323161, has a remarkable ability to find many sequences related to primes and prime chains. - Antti Karttunen, Jan 06 2019

Antti Karttunen, Table of n, a(n) for n = 1..65537
Index entries for sequences related to binary expansion of n

Cf. A004526, A039636, A305801, A323161.
A list of few similarly constructed sequences follows, where each sequence is an rgs-transform of such function f, for which the value of f(n) is the n-th term of the sequence whose A-number follows after a parenthesis, unless n is of the form ..., in which case f(n) is given a constant value outside of the range of that sequence:
  A322809 (A004526, unless an odd prime) [This sequence],
  A322589 (A007913, unless an odd prime),
  A322591 (A007947, unless an odd prime),
  A322805 (A252463, unless an odd prime),
  A323082 (A300840, unless an odd prime),
  A322822 (A300840, unless n > 2 and a Fermi-Dirac prime, A050376),
  A322988 (A322990, unless a prime power > 2),
  A323078 (A097246, unless an odd prime),
  A322808 (A097246, unless a squarefree number > 2),
  A322816 (A048675, unless an odd prime),
  A322807 (A285330, unless an odd prime),
  A322814 (A286621, unless an odd prime),
  A322824 (A242424, unless an odd prime),
  A322973 (A006370, unless an odd prime),
  A322974 (A049820, unless n > 1 and n is in A046642),
  A323079 (A060681, unless an odd prime),
  A322587 (A295887, unless an odd prime),
  A322588 (A291751, unless an odd prime),
  A322592 (A289625, unless an odd prime),
  A323369 (A323368, unless an odd prime),
  A323371 (A295886, unless an odd prime),
  A323374 (A323373, unless an odd prime),
  A323401 (A323372, unless an odd prime),
  A323405 (A323404, unless an odd prime).

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; };
A322809aux(n) = if((n>2)&&isprime(n),-1,(n>>1));
v322809 = rgs_transform(vector(up_to,n,A322809aux(n)));
A322809(n) = v322809[n];

a(n) = A323161(n+1) - 1.

A323237 Lexicographically earliest sequence such that for all i, j, a(i) = a(j) => f(i) = f(j), where f(n) = A291756(n) for all n, except f(1) = -1 and for odd numbers n > 1, f(n) = 0.

Original entry on oeis.org

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

Offset: 1

Antti Karttunen, Jan 08 2019

nonn

For all i, j:

A319701(i) = A319701(j) => a(i) = a(j) => A319998(i) = A319998(j).

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

Cf. A003557, A173557, A291756, A295887, A319701, A319998, A322587, A323238, A323241.

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; };
A003557(n) = { my(f=factor(n)); for(i=1, #f~, f[i, 2] = f[i, 2]-1); factorback(f); };
A173557(n) = my(f=factor(n)[, 1]); prod(k=1, #f, f[k]-1); \\ From A173557
Aux323237(n) = if(1==n,-1,if(n%2,0,(1/2)*(2 + ((A003557(n)+A173557(n))^2) - A003557(n) - 3*A173557(n))));
v323237 = rgs_transform(vector(up_to, n, Aux323237(n)));
A323237(n) = v323237[n];

A322355 Lexicographically earliest such sequence a that a(i) = a(j) => A322351(i) = A322351(j) and A322352(i) = A322352(j), for all i, j.

Original entry on oeis.org

1, 1, 2, 2, 3, 2, 4, 3, 5, 3, 6, 7, 8, 4, 9, 9, 10, 5, 11, 12, 8, 6, 13, 12, 14, 8, 15, 16, 17, 9, 18, 10, 19, 10, 20, 16, 21, 11, 20, 22, 23, 8, 24, 25, 26, 13, 27, 28, 29, 14, 30, 31, 32, 15, 23, 33, 21, 17, 34, 28, 35, 18, 36, 30, 37, 19, 38, 39, 40, 20, 41, 31, 42, 21, 43, 44, 35, 20, 45, 46, 47, 23, 48, 31, 49, 24, 50, 51, 52, 26, 42, 53, 35, 27, 42, 39, 54, 29

Offset: 1

Antti Karttunen, Dec 05 2018

nonn

Restricted growth sequence transform of the ordered pair [A322351(n), A322352(n)].
Essentially also the restricted growth sequence transform of the unordered pair {A003557(n), A173557(n)}.
For all i, j:
  A295887(i) = A295887(j) => a(i) = a(j),
  a(i) = a(j) => A322320(i) = A322320(j),
  a(i) = a(j) => A322321(i) = A322321(j),
  a(i) = a(j) => A000010(i) = A000010(j).

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

Cf. A000010, A003557, A173557, A295887, A322320, A322321, A322351, A322352.

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; };
A003557(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 2] = f[i, 2]-1); factorback(f); }; \\ From A003557
A173557(n) = factorback(apply(p -> p-1, factor(n)[, 1]));
A322351(n) = min(A003557(n), A173557(n));
A322352(n) = max(A003557(n), A173557(n));
v322355 = rgs_transform(vector(up_to, n, [A322351(n), A322352(n)]));
A322355(n) = v322355[n];

A323366 Lexicographically earliest sequence such that for all i, j, a(i) = a(j) => A000035(i) = A000035(j) and A003557(i) = A003557(j) and A173557(i) = A173557(j).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 13, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 34, 38, 39, 25, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 39, 52, 36, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 56, 65, 72, 73, 74, 75, 76, 49, 77, 78, 79, 80, 81, 82, 68, 83, 56, 84, 68, 85, 86, 87, 88, 89, 90, 91, 92, 93, 60

Offset: 1

Antti Karttunen, Jan 12 2019

nonn

For all i, j:
  a(i) = a(j) => A007814(i) = A007814(j),
  a(i) = a(j) => A295887(i) = A295887(j),
  a(i) = a(j) => A323237(i) = A323237(j).

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

Cf. A000035, A003557, A007814, A173557, A291756, A295887, A323237, A323367.

Cf. also A323368.

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; };
A003557(n) = { my(f=factor(n)); for(i=1, #f~, f[i, 2] = f[i, 2]-1); factorback(f); };
A173557(n) = my(f=factor(n)[, 1]); prod(k=1, #f, f[k]-1); \\ From A173557
v323366 = rgs_transform(vector(up_to, n, [(n%2), A003557(n), A173557(n)]));
A323366(n) = v323366[n];

A319999 Filter sequence combining A173557(n) with A319993(n).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 4, 8, 9, 10, 11, 12, 13, 14, 4, 15, 16, 17, 18, 12, 19, 20, 11, 21, 22, 23, 24, 25, 26, 27, 4, 28, 29, 30, 11, 31, 32, 30, 18, 33, 22, 34, 35, 36, 37, 38, 11, 39, 40, 41, 42, 43, 44, 33, 24, 31, 45, 46, 47, 48, 49, 50, 4, 51, 52, 53, 54, 55, 56, 57, 11, 58, 59, 60, 61, 48, 56, 62, 18, 63, 64, 65, 42, 66, 67, 68, 35, 69, 70, 58, 71, 48, 72, 58, 11, 73, 74, 75, 18, 76, 77, 78, 42

Offset: 1

Antti Karttunen, Nov 08 2018

nonn

Restricted growth sequence transform of ordered pair [A173557(n), A319993(n)].

For all i, j: a(i) = a(j) => A319997(i) = A319997(j).

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

Cf. A173557, A319993, A319997.

Cf. also A295886, A295887.

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; };
A173557(n) = factorback(apply(p -> p-1, factor(n)[, 1]));
A319993(n) =  { my(f=factor(n)); prod(i=1,#f~,if(2==f[i,1],-(1==f[i,2]),(f[i,1]^(f[i,2]-1)))); };
v319999 = rgs_transform(vector(up_to,n,[A173557(n),A319993(n)]));
A319999(n) = v319999[n];

cp's OEIS Frontend

A322587 Lexicographically earliest such sequence a that for all i, j, a(i) = a(j) => f(i) = f(j), where f(n) = 0 for odd primes, and f(n) = A291756(n) [equally: A295887(n)] for any other number.

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A291751 Lexicographically earliest such sequence a that a(i) = a(j) => A003557(i) = A003557(j) and A048250(i) = A048250(j), for all i, j.

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A295886 Filter-sequence combining A003557(n) and A023900(n).

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A295888 Filter combining prime signature of n (A101296) with Dedekind's psi (A001615).

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A322809 Lexicographically earliest such sequence a that a(i) = a(j) => f(i) = f(j) for all i, j, where f(n) = -1 if n is an odd prime, and f(n) = floor(n/2) for all other numbers.

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A323237 Lexicographically earliest sequence such that for all i, j, a(i) = a(j) => f(i) = f(j), where f(n) = A291756(n) for all n, except f(1) = -1 and for odd numbers n > 1, f(n) = 0.

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A322355 Lexicographically earliest such sequence a that a(i) = a(j) => A322351(i) = A322351(j) and A322352(i) = A322352(j), for all i, j.

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A323366 Lexicographically earliest sequence such that for all i, j, a(i) = a(j) => A000035(i) = A000035(j) and A003557(i) = A003557(j) and A173557(i) = A173557(j).

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Programs

PARI

A319999 Filter sequence combining A173557(n) with A319993(n).

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