A324386 -id:A324386 - cp's OEIS frontend

A324390 Lexicographically earliest positive sequence such that a(i) = a(j) => A278219(i) = A278219(j) and A324386(i) = A324386(j), for all i, j >= 0.

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

Offset: 0

Antti Karttunen, Feb 27 2019

nonn

Restricted growth sequence transform of the ordered pair [A278219(n), A324386(n)].

Cf. A278219, A324386.

Cf. also A286619, A324343, A324344, A324380 (compare the scatter-plots).

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 }; \\ From A005940
A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); }; \\ From A046523
A278222(n) = A046523(A005940(1+n));
A003188(n) = bitxor(n, n>>1);
A278219(n) = A278222(A003188(n));
Aux324390(n) = [A278219(n), A324386(n)]; \\ See code for A324386 in that entry.
v324390 = rgs_transform(vector(1+up_to,n,Aux324390(n-1)));
A324390(n) = v324390[1+n];

a(A000225(n)) = 2 for all n >= 1.

A324380 Lexicographically earliest positive sequence such that a(i) = a(j) => A069010(i) = A069010(j) and A324386(i) = A324386(j), for all i, j >= 0.

Original entry on oeis.org

1, 2, 3, 2, 3, 4, 3, 2, 5, 6, 6, 4, 3, 7, 8, 2, 3, 6, 9, 6, 6, 10, 11, 4, 12, 7, 13, 7, 14, 13, 12, 2, 5, 6, 7, 4, 9, 10, 9, 6, 7, 15, 16, 17, 18, 19, 18, 4, 12, 18, 6, 7, 20, 21, 22, 7, 23, 24, 25, 7, 26, 24, 26, 2, 8, 9, 9, 6, 11, 15, 7, 9, 11, 16, 27, 28, 25, 29, 25, 6, 18, 30, 21, 15, 31, 32, 19, 15, 33, 34, 16, 15, 35, 29, 33, 4, 36, 20, 24, 20, 37, 30, 24, 11

Offset: 0

Antti Karttunen, Feb 27 2019

nonn

Restricted growth sequence transform of the ordered pair [A069010(n), A324386(n)].

Cf. A069010, A324386.

Cf. also A324343, A324344, A324390.

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; };
A069010(n) = ((1 + (hammingweight(bitxor(n, n>>1)))) >> 1); \\ From A069010
Aux324380(n) = [A069010(n), A324386(n)]; \\ Code for A324386 available in that entry.
v324380 = rgs_transform(vector(1+up_to,n,Aux324380(n-1)));
A324380(n) = v324380[1+n];

a(A000225(n)) = 2 for all n >= 1.

A276150 Sum of digits when n is written in primorial base (A049345); minimal number of primorials (A002110) that add to n.

Original entry on oeis.org

0, 1, 1, 2, 2, 3, 1, 2, 2, 3, 3, 4, 2, 3, 3, 4, 4, 5, 3, 4, 4, 5, 5, 6, 4, 5, 5, 6, 6, 7, 1, 2, 2, 3, 3, 4, 2, 3, 3, 4, 4, 5, 3, 4, 4, 5, 5, 6, 4, 5, 5, 6, 6, 7, 5, 6, 6, 7, 7, 8, 2, 3, 3, 4, 4, 5, 3, 4, 4, 5, 5, 6, 4, 5, 5, 6, 6, 7, 5, 6, 6, 7, 7, 8, 6, 7, 7, 8, 8, 9, 3, 4, 4, 5, 5, 6, 4, 5, 5, 6, 6, 7, 5, 6, 6, 7, 7, 8, 6, 7, 7, 8, 8, 9, 7, 8, 8, 9, 9, 10, 4

Offset: 0

Antti Karttunen, Aug 22 2016

The sum of digits of n in primorial base is odd if n is 1 or 2 (mod 4) and even if n is 0 or 3 (mod 4). Proof: primorials are 1 or 2 (mod 4) and a(n) can be constructed via the greedy algorithm. So if n = 4k + r where 0 <= r < 4, 4k needs an even number of primorials and r needs hammingweight(r) = A000120(r) primorials. Q.E.D. - David A. Corneth, Feb 27 2019

			For n=24, which is "400" in primorial base (as 24 = 4*(3*2*1) + 0*(2*1) + 0*1, see A049345), the sum of digits is 4, thus a(24) = 4.

Antti Karttunen, Table of n, a(n) for n = 0..30030
Index entries for sequences related to primorial base

Cf. A000120, A001222, A002110, A049345, A053589, A235168, A260188, A267263, A276084, A276086, A276151, A277022, A278226, A283477, A319713, A319715 (inverse Möbius transform), A321683, A324342, A324382, A324383, A324386, A324387, A371091, A373605, A373606, A373607.
Cf. A333426 [k such that a(k)|k], A339215 [numbers not of the form x+a(x) for any x], A358977 [k such that gcd(k, a(k)) = 1].
Cf. A338835, A366693.
Cf. A014601, A042963 (positions of even and odd terms), A343048 (positions of records).
Differs from analogous A034968 for the first time at n=24.

nn = 120; b = MixedRadix[Reverse@ Prime@ NestWhileList[# + 1 &, 1, Times @@ Prime@ Range[# + 1] <= nn &]]; Table[Total@ IntegerDigits[n, b], {n, 0, nn}] (* Version 10.2, or *)
nn = 120; f[n_] := Block[{a = {{0, n}}}, Do[AppendTo[a, {First@ #, Last@ #} &@ QuotientRemainder[a[[-1, -1]], Times @@ Prime@ Range[# - i]]], {i, 0, #}] &@ NestWhile[# + 1 &, 0, Times @@ Prime@ Range[# + 1] <= n &]; Rest[a][[All, 1]]]; Table[Total@ f@ n, {n, 0, 120}] (* Michael De Vlieger, Aug 26 2016 *)

A276150(n) = { my(s=0, p=2, d); while(n, d = (n%p); s += d; n = (n-d)/p; p = nextprime(1+p)); (s); }; \\ Antti Karttunen, Feb 27 2019

from sympy import prime, primefactors
def Omega(n): return 0 if n==1 else Omega(n//primefactors(n)[0]) + 1
def a276086(n):
    i=0
    m=pr=1
    while n>0:
        i+=1
        N=prime(i)*pr
        if n%N!=0:
            m*=(prime(i)**((n%N)/pr))
            n-=n%N
        pr=N
    return m
def a(n): return Omega(a276086(n))
print([a(n) for n in range(201)]) # Indranil Ghosh, Jun 23 2017

a(n) = 1 + a(A276151(n)) = 1 + a(n-A002110(A276084(n))), a(0) = 0.
or for n >= 1: a(n) = 1 + a(n-A260188(n)).
Other identities and observations. For all n >= 0:
a(n) = A001222(A276086(n)) = A001222(A278226(n)).
a(n) >= A371091(n) >= A267263(n).
From Antti Karttunen, Feb 27 2019: (Start)
a(n) = A000120(A277022(n)).
a(A283477(n)) = A324342(n).
(End)
a(n) = A373606(n) + A373607(n). - Antti Karttunen, Jun 19 2024

A324888 Minimal number of primorials (A002110) that add to A108951(n).

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 1, 2, 2, 2, 1, 4, 1, 2, 6, 4, 1, 4, 1, 4, 6, 2, 1, 4, 6, 2, 2, 4, 1, 6, 1, 2, 6, 2, 10, 8, 1, 2, 6, 2, 1, 2, 1, 4, 6, 2, 1, 4, 8, 12, 6, 4, 1, 4, 6, 8, 6, 2, 1, 6, 1, 2, 6, 4, 14, 12, 1, 4, 6, 10, 1, 6, 1, 2, 10, 4, 18, 12, 1, 4, 8, 2, 1, 4, 12, 2, 6, 8, 1, 12, 18, 4, 6, 2, 8, 8, 1, 16, 12, 8, 1, 12, 1, 8, 8

Offset: 1

Antti Karttunen, Mar 30 2019

nonn

Sum of digits when A108951(n) is written in primorial base (A049345).

Cf. A001222, A002110, A034386, A049345, A108951, A276086, A276150, A324886.

Cf. A324383, A324386, A324387 (permutations of this sequence).

With[{b = Reverse@ Prime@ Range@ 120}, Array[Total@ IntegerDigits[#, MixedRadix[b]] &@ Apply[Times, Map[#1^#2 & @@ # &, FactorInteger[#] /. {p_, e_} /; e > 0 :> {Times @@ Prime@ Range@ PrimePi@ p, e}]] &, 105] ] (* Michael De Vlieger, Nov 18 2019 *)

A034386(n) = prod(i=1, primepi(n), prime(i));
A108951(n) = { my(f=factor(n)); prod(i=1, #f~, A034386(f[i, 1])^f[i, 2]) };  \\ From A108951
A276150(n) = { my(s=0,m); forprime(p=2, , if(!n, return(s)); m = n%p; s += m; n = (n-m)/p); };
A324888(n) = A276150(A108951(n));

a(n) = A276150(A108951(n)).

a(n) = A001222(A324886(n)).

A324387 Minimal number of primorials (A002110) that add to the n-th number that is a product of primorials: a(n) = A276150(A025487(n)).

Original entry on oeis.org

1, 1, 2, 1, 2, 2, 4, 4, 1, 2, 2, 4, 2, 4, 4, 4, 4, 6, 8, 6, 8, 1, 2, 2, 6, 6, 6, 10, 2, 4, 4, 6, 8, 6, 10, 4, 8, 6, 8, 12, 6, 10, 6, 8, 12, 10, 8, 12, 12, 10, 16, 12, 20, 1, 2, 6, 8, 10, 6, 10, 8, 10, 16, 14, 20, 2, 4, 12, 10, 10, 14, 10, 16, 12, 20, 6, 6, 10, 8, 10, 12, 20, 4, 8, 14, 14, 20, 14, 10, 16, 14, 24, 6, 12, 12

Offset: 1

Antti Karttunen, Feb 27 2019

nonn

A098719 gives the positions of ones in this sequence. See also comments in A324383.

Antti Karttunen, Table of n, a(n) for n = 1..10001 (based on the b-file of A025487 as computed by Will Nicholes and Franklin T. Adams-Watters)
Index entries for sequences related to primorial base
Index entries for sequences related to primorial numbers

Cf. A002110, A025487, A098719 (positions of ones), A276150, A324342.

Cf. A324382 for a subsequence, and A324383, A324386 for permutations of this sequence.

A276150(n) = { my(s=0,m); forprime(p=2, , if(!n, return(s)); m = n%p; s += m; n = (n-m)/p); };
A324387(n) = A276150(A025487(n));

a(n) = A276150(A025487(n)).

A324383 a(n) is the minimal number of primorials that add to A322827(n).

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 2, 2, 2, 6, 1, 6, 4, 2, 4, 4, 8, 6, 6, 10, 8, 1, 10, 22, 4, 6, 2, 12, 8, 4, 4, 2, 8, 16, 6, 4, 24, 6, 8, 14, 26, 18, 1, 26, 20, 6, 18, 30, 6, 12, 2, 14, 16, 2, 10, 16, 8, 6, 4, 8, 6, 2, 4, 4, 12, 14, 14, 18, 18, 12, 16, 32, 42, 28, 6, 22, 32, 24, 24, 42, 46, 32, 18, 20, 30, 1, 24, 54, 38, 26, 14, 44, 34, 8

Offset: 0

Antti Karttunen, Feb 27 2019

nonn

a(n) is odd if and only if n is one of the terms of A000975: 1, 2, 5, 10, 21, 42, 85, ..., in which case A322827(n) will be one of primorials (A002110), and a(n) = 1. This happens because A276150 is even for all multiples of four, and a product of two or more primorials > 1 is always a multiple of 4. Note that the same property does not hold in factorial system: 36 = 3!*3!, but A034968(36) = 3 as 36 = 4!+3!+3!.

Cf. A000975 (positions of ones), A002110, A003188, A025487, A276150, A322827, A324342, A324382.

Cf. also A324386, A324387 (permutations of this sequence).

A276150(n) = { my(s=0,m); forprime(p=2, , if(!n, return(s)); m = n%p; s += m; n = (n-m)/p); };
A322827(n) = if(!n,1,my(bits = Vecrev(binary(n)), rl=1, o = List([])); for(i=2,#bits,if(bits[i]==bits[i-1], rl++, listput(o,rl))); listput(o,rl); my(es=Vecrev(Vec(o)), m=1); for(i=1,#es,m *= prime(i)^es[i]); (m));
A324383(n) = A276150(A322827(n));

a(n) = A276150(A322827(n)).

a(n) = A324386(A003188(n)).

cp's OEIS Frontend

A324390 Lexicographically earliest positive sequence such that a(i) = a(j) => A278219(i) = A278219(j) and A324386(i) = A324386(j), for all i, j >= 0.

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A324380 Lexicographically earliest positive sequence such that a(i) = a(j) => A069010(i) = A069010(j) and A324386(i) = A324386(j), for all i, j >= 0.

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A276150 Sum of digits when n is written in primorial base (A049345); minimal number of primorials (A002110) that add to n.

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A324888 Minimal number of primorials (A002110) that add to A108951(n).

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A324387 Minimal number of primorials (A002110) that add to the n-th number that is a product of primorials: a(n) = A276150(A025487(n)).

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A324383 a(n) is the minimal number of primorials that add to A322827(n).

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