A343191 Squiggle Dot Numbers: numbers generated in a similar way to those in A010790 except that every prime number is divided instead of multiplied. The result is then rounded to the closest integer.

1, 1, 0, 0, 0, 0, 0, 0, 8, 677, 616, 671, 620, 668, 140180, 33643245, 31664230, 33526832, 31762262, 33433960, 14042263246, 6487525619781, 6205459288487, 6475261866247, 3885157119748074, 2525352127836247843, 1772797193741045985945, 1340234678468230765374557, 1294019689555533152775435

Offset

1,9

Links

Table of n, a(n) for n=1..29.

Formula

a(n) = round(n^(2*A010051(n)-1)*(A000142(n)/A034386(n)^2)^2.

Example

              / 1*4*6*8*9*10*9*8*6*4*1 \
a(10) = round | ---------------------- |             = 677;
              \    2*3*5*7 * 7*5*3*2   /
              / 1*4*6*8*9*10*10*9*8*6*4*1 \
a(11) = round | ------------------------- |          = 616;
              \     2*3*5*7*11*7*5*3*2    /
              / 1*4*6*8*9*10*12*10*9*8*6*4*1 \
a(12) = round | ----------------------------- |      = 671;
              \    2*3*5*7*11*11*7*5*3*2     /
              / 1*4*6*8*9*10*12*12*10*9*8*6*4*1 \
a(13) = round | ------------------------------- |    = 620.
              \    2*3*5*7*11*13*11*7*5*3*2     /

Prog

(PARI) sqdot(n)={my(s=if(isprime(n), 1/n, n)); for(k=2, n-1, my(kk=k*k); if(isprime(k), s/=kk, s*=kk)); round(s)};
for(k=1, 29, print1(sqdot(k), ", ")) \\ Hugo Pfoertner, Apr 07 2021

Crossrefs

Cf. A010790.

Sequence in context: A199801 A278857 A334088 * A202910 A332168 A168130

Adjacent sequences: A343188 A343189 A343190 * A343192 A343193 A343194

Keyword

nonn,easy

Author

Brian Labore, Apr 07 2021

Status

approved