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A378159
The least prime dividing A000255(n); a(1) = 1.
2
1, 3, 11, 53, 3, 13, 11, 3, 1468457, 11, 3, 1373, 34361893981, 3, 17713, 2130617, 3, 11, 13, 3, 11, 617, 3, 37, 11, 3, 179, 14633, 3, 76463, 97, 3, 337, 1049, 3, 11, 7237598635049, 3, 67, 11, 3, 22742406079421034331584846001936724930824184898296683, 11, 3, 13
OFFSET
1,2
LINKS
FORMULA
a(n) = A020639(A000255(n)).
a(n) = A000255(n) if and only if n+2 is a term of A301423.
a(3*n-1) = 3.
MATHEMATICA
FactorInteger[#][[1, 1]] & /@ Table[Subfactorial[n + 2]/(n + 1), {n, 1, 44}]
PROG
(PARI) lpf(n) = if(n == 1, 1, factor(n)[1, 1]);
lista(nmax) = {my(s = 1); for(n = 1, nmax, s = (n * (n+2) * s + (-1)^n)/(n+1); print1(lpf(s), ", ")); }
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Nov 18 2024
STATUS
approved