A364502 -id:A364502 - cp's OEIS frontend

A365431 Lexicographically earliest infinite sequence such that a(i) = a(j) => A364502(i) = A364502(j) for all i, j >= 1, where A364502(n) is the denominator of n / A005940(n).

1, 1, 1, 1, 1, 1, 2, 1, 3, 1, 4, 1, 5, 2, 2, 1, 6, 3, 7, 1, 8, 4, 9, 1, 10, 5, 5, 2, 11, 2, 12, 1, 13, 6, 14, 3, 15, 7, 7, 1, 16, 8, 17, 4, 18, 9, 19, 1, 20, 10, 10, 5, 21, 5, 9, 2, 22, 11, 23, 2, 24, 12, 25, 1, 26, 13, 27, 6, 28, 14, 29, 3, 30, 15, 6, 7, 5, 7, 31, 1, 32, 16, 33, 8, 16, 17, 17, 4, 34, 18, 35, 9, 36, 19, 12, 1

Offset: 1

Antti Karttunen, Sep 07 2023

Restricted growth sequence transform of A364502, or equally, of A365432.
For all i, j: A003602(i) = A003602(j) => a(i) = a(j).
Compare to the scatter plots of A365393 and A365715.

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

Cf. A005940, A364502, A365432.

Cf. also A365393, A365715 (analogous sequence for Doudna variant D(3)).

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; };
A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t };
A364502(n) = { my(u=A005940(n)); (u / gcd(n, u)); };
v365431 = rgs_transform(vector(up_to,n,A364502(n)));
A365431(n) = v365431[n];

A365432 a(n) = A156552(A364502(n)), where A364502(n) = A005940(n) / gcd(n, A005940(n)), and A156552 is the inverse of offset-0 version of Doudna-sequence A005940.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 6, 0, 8, 0, 10, 0, 12, 6, 6, 0, 16, 8, 18, 0, 4, 10, 22, 0, 24, 12, 12, 6, 28, 6, 30, 0, 32, 16, 34, 8, 36, 18, 18, 0, 40, 4, 42, 10, 20, 22, 46, 0, 48, 24, 24, 12, 52, 12, 22, 6, 56, 28, 58, 6, 60, 30, 14, 0, 64, 32, 66, 16, 68, 34, 70, 8, 72, 36, 16, 18, 12, 18, 78, 0, 80, 40, 82, 4, 40, 42, 42, 10

Offset: 1

Antti Karttunen, Sep 07 2023

nonn

Antti Karttunen, Table of n, a(n) for n = 1..16384

Cf. A005940, A364500, A341520, A365430, A365431 (rgs-transform).

A156552(n) = {my(f = factor(n), p, 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
A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t };
A364502(n) = { my(u=A005940(n)); (u / gcd(n, u)); };
A365432(n) = A156552(A364502(n));

For all n >= 1, a(n) <= n-1 and A341520(a(n), A365430(n)) = n-1.

A364500 a(n) = gcd(n, A005940(n)).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 1, 8, 1, 10, 1, 12, 1, 2, 3, 16, 1, 2, 1, 20, 7, 2, 1, 24, 1, 2, 3, 4, 1, 6, 1, 32, 1, 2, 1, 4, 1, 2, 3, 40, 1, 14, 1, 4, 5, 2, 1, 48, 1, 2, 3, 4, 1, 6, 5, 8, 1, 2, 1, 12, 1, 2, 9, 64, 1, 2, 1, 4, 1, 2, 1, 8, 1, 2, 15, 4, 11, 6, 1, 80, 1, 2, 1, 28, 5, 2, 3, 8, 1, 10, 7, 4, 1, 2, 5, 96, 1, 2, 33, 4

Offset: 1

Antti Karttunen, Jul 28 2023

nonn

Antti Karttunen, Table of n, a(n) for n = 1..16384
Index entries for sequences related to binary expansion of n

Cf. A005940, A364499, A364501, A364502.

Cf. also A324198, A339969, A364255.

nn = 100; Array[Set[a[#], #] &, 2]; Do[If[EvenQ[n], Set[a[n], 2 a[n/2]], Set[a[n], Times @@ Power @@@ Map[{Prime[PrimePi[#1] + 1], #2} & @@ # &, FactorInteger[a[(n + 1)/2]]]]], {n, 3, nn}]; Array[GCD[a[#], #] &, nn] (* Michael De Vlieger, Jul 28 2023 *)

A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t };
A364500(n) = gcd(n, A005940(n));

A364500(n) = { my(orgn=n,p=2,rl=0,z=1); n--; while(n, if(!(n%2), p=nextprime(1+p), rl++; if(1==(n%4), z *= p^min(rl,valuation(orgn,p)); rl=0)); n>>=1); (z); };

a(n) = gcd(n, A364499(n)) = gcd(A005940(n), A364499(n)).

a(n) = n / A364501(n) = A005940(n) / A364502(n).

A364501 a(n) = n / gcd(n, A005940(n)).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 7, 1, 9, 1, 11, 1, 13, 7, 5, 1, 17, 9, 19, 1, 3, 11, 23, 1, 25, 13, 9, 7, 29, 5, 31, 1, 33, 17, 35, 9, 37, 19, 13, 1, 41, 3, 43, 11, 9, 23, 47, 1, 49, 25, 17, 13, 53, 9, 11, 7, 57, 29, 59, 5, 61, 31, 7, 1, 65, 33, 67, 17, 69, 35, 71, 9, 73, 37, 5, 19, 7, 13, 79, 1, 81, 41, 83, 3, 17, 43, 29, 11, 89

Offset: 1

Antti Karttunen, Jul 28 2023

Numerator of n / A005940(n).

Antti Karttunen, Table of n, a(n) for n = 1..16384
Index entries for sequences related to binary expansion of n

Cf. A005940, A364500, A364502 (denominators), A364544 (positions of 1's).

Cf. also A364491.

nn = 89; Array[Set[a[#], #] &, 2]; Do[If[EvenQ[n], Set[a[n], 2 a[n/2]], Set[a[n], Times @@ Power @@@ Map[{Prime[PrimePi[#1] + 1], #2} & @@ # &, FactorInteger[a[(n + 1)/2]]]]], {n, 3, nn}]; Array[#/GCD[a[#], #] &, nn] (* Michael De Vlieger, Jul 28 2023 *)

A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t };
A364501(n) = (n / gcd(n, A005940(n)));

A364501(n) = { my(orgn=n,p=2,rl=0,z=1); n--; while(n, if(!(n%2), p=nextprime(1+p), rl++; if(1==(n%4), z *= p^min(rl,valuation(orgn,p)); rl=0)); n>>=1); (orgn/z); };

A364546 Numbers k such that k is a multiple of A005940(k).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 8, 10, 12, 16, 20, 24, 32, 40, 48, 64, 80, 96, 128, 160, 192, 256, 320, 384, 512, 640, 768, 1024, 1035, 1280, 1536, 2048, 2070, 2560, 3072, 4096, 4140, 5120, 6144, 8192, 8280, 10240, 12288, 16384, 16560, 20480, 24576, 32768, 33120, 40960, 49152, 65536, 66240, 81920, 98304, 131072, 132480, 163840

Offset: 1

Antti Karttunen, Jul 28 2023

nonn

Sequence A005941(A364548(.)) sorted into ascending order.
If k is a term, then also 2*k is present in this sequence, and vice versa.
A029747 is included as a subsequence, because it gives the known fixed points of map n -> A005940(n).

Positions of 1's in A364502.
Subsequence of A364541.
Subsequences: A029747, A364547 (odd terms).
Cf. A005940, A364544, A364548.
Cf. also A364496.

nn = 2^18; Array[Set[a[#], #] &, 2]; Do[If[EvenQ[n], Set[a[n], 2 a[n/2]], Set[a[n], Times @@ Power @@@ Map[{Prime[PrimePi[#1] + 1], #2} & @@ # &, FactorInteger[a[(n + 1)/2]]]]], {n, 3, nn}]; Select[Range[nn], Divisible[#, a[#]] &] (* Michael De Vlieger, Jul 28 2023 *)

A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t };
isA364546(n) = !(n%A005940(n));

A364547 Odd numbers k such that k is a multiple of A005940(k).

Original entry on oeis.org

1, 3, 5, 1035, 524295, 16777217

Offset: 1

Antti Karttunen, Jul 28 2023

Sequence A005941(A364549(.)) sorted into ascending order.
Those terms of A000051 (= 2^k + 1) are included that have A000040(1+k) as one of their prime factors.
a(7) > 402653184.
See also comments in A364963. - Antti Karttunen, Jan 12 2024

			1035 is included because 1034 in binary is "10000001010", which Doudna isomorphism maps to 345 = 3*5*23, which thus divides 1035 (= 3^2 * 5 * 23). Note that there are six 0's in the binary representation between its most significant bit and the trailing "1010", thus we get the prime factors A000040(1+1) = 3, A000040(1+1+1) = 5 and A000040(1+1+1+6) = 23.
524295 is included because 524294 in binary is "10000000000000000110", which Doudna isomorphism maps to 549 = 3^2 * 61, which thus divides 524295 (= 3^2 * 5 * 61 * 191). Note that there are sixteen 0's in the binary representation between its most significant bit and the trailing "110", thus we get the prime factors A000040(2) = 3 and A000040(2+16) = 61.
16777217 = 2^24 + 1 is included because A000040(1+24) = 97, and 16777217 = 97*257*673.

Odd terms in A364546.
Cf. A000040, A000051, A005940, A005941, A364502, A364549.
Cf. also A364545, A364551, A364963.

nn = 2^20 + 2; Array[Set[a[#], #] &, 2]; {1}~Join~Reap[Do[If[EvenQ[n], Set[a[n], 2 a[n/2]], a[n] = k = Times @@ Power @@@ Map[{Prime[PrimePi[#1] + 1], #2} & @@ # &, FactorInteger[a[(n + 1)/2]]]; If[Divisible[n, a[n]], Sow[n]]], {n, 3, nn}] ][[-1, 1]] (* Michael De Vlieger, Jul 28 2023 *)

A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t };
isA364547(n) = ((n%2)&&!(n%A005940(n)));

A365465 a(n) = A356867(n) / gcd(n, A356867(n)).

Original entry on oeis.org

1, 1, 1, 5, 4, 1, 10, 1, 1, 7, 14, 5, 25, 10, 4, 25, 16, 1, 35, 7, 10, 125, 40, 1, 4, 16, 1, 11, 22, 7, 55, 11, 14, 35, 8, 5, 49, 49, 25, 35, 140, 10, 250, 20, 4, 245, 196, 25, 625, 4, 16, 125, 64, 1, 7, 55, 35, 275, 88, 7, 350, 56, 10, 343, 98, 125, 875, 70, 40, 125, 160, 1, 1225, 196, 4, 3125, 400, 16, 1000, 8, 1, 13, 26

Offset: 1

Antti Karttunen, Sep 15 2023

nonn

Denominator of n / A356867(n).

Antti Karttunen, Table of n, a(n) for n = 1..19683

Cf. A356867, A365462, A365463, A365464 (numerators).

Cf. also A364502.

up_to = 19683;
A356867list(up_to) = { my(v=vector(up_to),met=Map(),h=0,ak); for(i=1,#v,if(1==vecsum(digits(i,3)), v[i] = i; h = i, ak = v[i-h]; forprime(p=2,,if(3!=p && !mapisdefined(met,p*ak), v[i] = p*ak; break))); mapput(met,v[i],i)); (v); };
v356867 = A356867list(up_to);
A356867(n) = v356867[n];
A365465(n) = (A356867(n)/gcd(n, A356867(n)));

a(n) = A356867(n) / A365463(n).

cp's OEIS Frontend

A365431 Lexicographically earliest infinite sequence such that a(i) = a(j) => A364502(i) = A364502(j) for all i, j >= 1, where A364502(n) is the denominator of n / A005940(n).

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A365432 a(n) = A156552(A364502(n)), where A364502(n) = A005940(n) / gcd(n, A005940(n)), and A156552 is the inverse of offset-0 version of Doudna-sequence A005940.

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A364500 a(n) = gcd(n, A005940(n)).

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A364501 a(n) = n / gcd(n, A005940(n)).

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A364546 Numbers k such that k is a multiple of A005940(k).

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A364547 Odd numbers k such that k is a multiple of A005940(k).

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A365465 a(n) = A356867(n) / gcd(n, A356867(n)).

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