A356953 Least nonzero starting number in the first run of exactly n consecutive numbers having the same number of prime factors counted with multiplicity, or -1 if no such number exists.

1, 2, 33, 1083, 602, 2522, 211673, 6612470, 3405122, 49799889, 202536181, 3195380868, 5208143601, 85843948321, 97524222465

Offset

1,2

Comments

In the definition, "exactly" means the run is not part of a longer run.

Links

Table of n, a(n) for n=1..15.

Example

2 and 3 are 2 consecutive numbers and have the same number of prime factors, and 2 is the smallest such number, hence a(2) = 2.

Prog

(PARI) card(m)=my(c=0, k=bigomega(m)); if(bigomega(m-1)!=k, while(bigomega(m)==k, c++; m++)); c
a(n)=if(n==1, return(1)); for(m=2, +oo, if(card(m)==n, return(m)))

Crossrefs

Cf. A001222, A077657, A356855.

Cf. A045920, A115186, A113752, A356893.

Sequence in context: A077657 A219342 A256278 * A204239 A198901 A242621

Adjacent sequences: A356950 A356951 A356952 * A356954 A356955 A356956

Keyword

nonn,more

Author

Jean-Marc Rebert, Sep 06 2022

Status

approved