A353518 a(n) = 1 if n is a product of superprimorials (A006939), otherwise 0.

1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1

Offset

1

Links

Antti Karttunen, Table of n, a(n) for n = 1..103680

Index entries for characteristic functions

Formula

For all n >= 1, a(n) <= A322585(n) <= A341629(n).

Prog

(PARI)
firstdiffs0forward(vec) = { my(v=vector(#vec)); for(n=1, #v, v[n] = vec[n]-if(#v==n, 0, vec[1+n])); (v); };
A353518(n) = if(1==n, 1, my(f=factor(n), len=#f~); if(primepi(f[len, 1])!=len, return(0), my(diffs=firstdiffs0forward(f[, 2])); for(i=1, #diffs-1, if(diffs[i+1]>diffs[i], return(0))); (1)));

Crossrefs

Characteristic function of A181818.

Cf. A006939, A322585, A341629.

Sequence in context: A354193 A354188 A342025 * A353687 A354918 A354108

Adjacent sequences: A353515 A353516 A353517 * A353519 A353520 A353521

Keyword

nonn

Author

Antti Karttunen, Apr 28 2022

Status

approved