A369558 - OEIS

A369558

a(n) is the minimum value of k > 0 such that A075860(n) = A075860(n+k) with n > 1.

2, 6, 4, 1, 6, 3, 7, 5, 10, 110, 6, 9, 13, 1, 10, 193, 6, 15, 1, 9, 22, 250, 1, 10, 6, 1, 5, 370, 8, 27, 7, 23, 34, 1, 6, 398, 2, 6, 9, 610, 4, 39, 13, 7, 2, 730, 6, 1, 1, 9, 3, 850, 11, 9, 6, 28, 58, 1586, 3, 57, 8, 13, 2, 7, 3, 818, 25, 5, 11, 1210, 5, 69, 1, 11

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OFFSET

2,1

LINKS

Table of n, a(n) for n=2..75.

EXAMPLE

For n=5, A075860(5) = A075860(5+1), so a(5)=1.

For n=15, A075860(15) = A075860(15+1), so a(15)=1.

MAPLE

f := proc(n) option remember;

if isprime(n) then

else

procname(convert(numtheory:-factorset(n), `+`));

fi;

end proc:

g := proc(n)

local k;

for k from 1 do

if f(n+k) = f(n) then

return k;

fi;

end do;

end proc:

map(g, [$2..100]);

PROG

(PARI) fp(n, pn) = if (n == pn, n, fp(vecsum(factor(n)[, 1]), n));

f(n) = if (n==1, 0, fp(n, 0));

a(n) = my(k=1, fn=f(n)); while(f(n+k) != fn, k++); k; \\ Michel Marcus, Feb 20 2024

CROSSREFS

Cf. A075860.

Sequence in context: A059574 A332395 A004600 * A370673 A325497 A021795

Adjacent sequences: A369555 A369556 A369557 * A369559 A369560 A369561

KEYWORD

nonn

AUTHOR

Rafik Khalfi, Jan 25 2024

STATUS

approved