A348187 - OEIS

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A348187

Integers m with k digits (for some k) that lie in an interval of k integers and the digits of m are the total number of distinct prime factors of all the integers in that interval.

12, 22, 31, 122, 132, 312, 322, 2323, 3312, 14421, 23222, 24243, 33333, 51243, 333424, 342332, 432241, 523233, 1333232, 1432243, 2424341, 2442253, 5134334, 15232343, 24243232, 24424243, 25514234, 26134354, 32334533, 33252335, 33341415, 33343412, 34332425, 43523432, 53224343

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..35.

EXAMPLE

12 is term because omega([11, 12]) gives [1, 2], the digits of 12.

33333 is a term because omega([33332, 33333, 33334, 33335, 33336]) but also omega([33333, 33334, 33335, 33336, 33337]) both give [3, 3, 3, 3, 3].

PROG

(PARI) vecn(n) = {my(list = List()); for (k=10^(n-1), 10^n-1-n, my(w = apply(omega, vector(n, i, k+i-1))); my(m = fromdigits(w)); if ((m>=k) && (m<=k+n-1), listput(list, m)); ); Set(list); }

lista(nn) = {my(list = List()); for (n=1, nn, my(w=vecn(n)); for (k=1, #w, listput(list, w[k])); ); Set(list); }

CROSSREFS

Cf. A001221 (omega), A323083 (following), A348266 (preceding).

Sequence in context: A078538 A278030 A286094 * A098955 A285470 A124885

Adjacent sequences: A348184 A348185 A348186 * A348188 A348189 A348190

KEYWORD

nonn,base

AUTHOR

Michel Marcus, Oct 12 2021

STATUS

approved