A364572 -id:A364572 - cp's OEIS frontend

A364499 a(n) = A005940(n) - n.

0, 0, 0, 0, 0, 0, 2, 0, -2, 0, 4, 0, 12, 4, 12, 0, -6, -4, 2, 0, 14, 8, 22, 0, 24, 24, 48, 8, 96, 24, 50, 0, -20, -12, -2, -8, 18, 4, 24, 0, 36, 28, 62, 16, 130, 44, 88, 0, 72, 48, 96, 48, 192, 96, 170, 16, 286, 192, 316, 48, 564, 100, 180, 0, -48, -40, -28, -24, -4, -4, 28, -16, 18, 36, 90, 8, 198, 48, 110, 0, 62

Offset: 1

Antti Karttunen, Jul 28 2023

Compare to the scatter plot of A364563.
From Antti Karttunen, Aug 11 2023: (Start)
Can be computed as a certain kind of bitmask transformation of A364568 (analogous to the inverse Möbius transform that is appropriate for A156552-encoding of n).
See A364572, A364573 (and also A364576) for n (apart from those in A029747) where a(n) comes relatively close to the X-axis.
(End)

			A005940(528577) = 528581, therefore a(528577) = 528581 - 528577 = 4. (See A364576).
A005940(2109697) = 2109629, therefore a(2109697) = 2109629 - 2109697 = -68.

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

Cf. A005940, A364500 [= gcd(n,a(n))], A364559, A364572, A364573, A364576.
Cf. A029747 (known positions of 0's), A364540 (positions of terms < 0), A364541 (of terms <= 0), A364542 (of terms >= 0), A364563 [= -a(A364543(n))].
Cf. also A364258, A364568.

nn = 81; 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[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 };
A364499(n) = (A005940(n)-n);

A364499(n) = { my(m=1,p=2,x=0,z=1); n--; while(n, if(!(n%2), p=nextprime(1+p), x += m; z *= p); n>>=1; m <<=1); (z-x)-1; }; \\ Antti Karttunen, Aug 06 2023

from math import prod
from itertools import accumulate
from collections import Counter
from sympy import prime
def A364499(n): return prod(prime(len(a)+1)**b for a, b in Counter(accumulate(bin(n-1)[2:].split('1')[:0:-1])).items())-n # Chai Wah Wu, Aug 07 2023

a(n) = -A364559(A005940(n)).
For all n >= 1, a(2*n) = 2*a(n).
For all n >= 1, a(A029747(n)) = 0.

A364576 Starting from k=1, each subsequent term is the next larger odd k such that A156552(k) < k and the ratio A156552(k)/k is nearer to 1.0 than for any previous k in the sequence.

Original entry on oeis.org

1, 3, 5, 21, 323, 66297, 139965, 263375, 264845, 528581

Offset: 1

Antti Karttunen, Aug 06 2023

All the odd fixed points of map n -> A005940(n) [and its inverse, map n -> A005941(n)] are included in this sequence. This includes both the known odd fixed points, 1, 3 and 5 (see A029747), and any additional hypothetical odd composites that would satisfy the condition n == A005940(n).

This is a subsequence of A364561, so the comments given in A364564 apply also here.

			       k  A156552(k)    A156552(k)/k  k-(1+A156552(k)) factorization of k
       1:       0         0                0
       3:       2         0.6666667        0
       5:       4         0.8              0
      21:      18         0.8571429        2           (3 * 7)
     323:     320         0.9907121        2           (17 * 19)
   66297:   65714         0.9912062      582           (3 * 7^2 * 11 * 41)
  139965:  139306         0.9952917      658           (3 * 5 * 7 * 31 * 43)
  263375:  262364         0.9961614     1010           (5^3 * 7^2 * 43)
  264845:  264244         0.9977307      600           (5 * 7^2 * 23 * 47)
  528581:  528576         0.9999905        4           (17^2 * 31 * 59).

Subsequence of A364561.
Cf. A005940, A005941, A029747, A156552.
Cf. also A364551, A364564, A364572.

A364573 Starting from k=9, each subsequent term is the next larger odd k such that A005940(k) <= k and the ratio A005940(k)/k is nearer to 1.0 than for any previous k in the sequence.

Original entry on oeis.org

9, 35, 267, 8353, 16475, 16543, 132175, 262563, 295175, 1115151, 2098057, 2109697, 8651313, 537938015, 1073787425

Offset: 1

Antti Karttunen, Aug 06 2023

			           k     A005940(k)  A005940(k)/k  k-A005940(k)
           9             7    0.7777778          2
          35            33    0.9428571          2
         267           255    0.9550562         12
        8353          8177    0.9789297        176
       16475         16275    0.9878604        200
       16543         16443    0.9939551        100
      132175        131733    0.9966560        442
      262563        262119    0.9983090        444
      295175        294831    0.9988346        344
     1115151       1114749    0.9996395        402
     2098057       2097851    0.9999018        206
     2109697       2109629    0.9999678         68
     8651313       8651137    0.9999797        176
   537938015     537931935    0.9999887       6080
  1073787425    1073785843    0.9999985       1582.

Cf. A005940, A364563, A364572, A364576.

print1(9,", "); r = A005940(9)/9; forstep(n=9,1+(2^31),2,t=A005940(n)/n; if(t<=1 && t > r, r=t;print1(n, ", ")))

cp's OEIS Frontend

A364499 a(n) = A005940(n) - n.

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A364576 Starting from k=1, each subsequent term is the next larger odd k such that A156552(k) < k and the ratio A156552(k)/k is nearer to 1.0 than for any previous k in the sequence.

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A364573 Starting from k=9, each subsequent term is the next larger odd k such that A005940(k) <= k and the ratio A005940(k)/k is nearer to 1.0 than for any previous k in the sequence.

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PARI