A354603 - OEIS

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A354603

Numbers k such that sum of distinct primes dividing k is equal to the sum of proper divisors of k+1.

3, 7, 14, 31, 127, 206, 2974, 8191, 19358, 20490, 131071, 147454, 286122, 289650, 292332, 441276, 524287, 909498, 1207358, 1657968, 1782540, 2490042, 3368860, 9274806, 11367402, 14107852, 16776156, 18589386, 22910988, 24450316, 26867718, 28959606, 32674506, 33163372

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OFFSET

1,1

COMMENTS

Numbers k such that A008472(k) = A001065(k+1). All Mersenne primes are terms.

LINKS

Table of n, a(n) for n=1..34.

EXAMPLE

Example: 14 is a term because A008472(14) = 2+7 = A001065(15) = 1+3+5.

MATHEMATICA

Select[Range[19358], Sum[f, {f, Select[Divisors[#], PrimeQ]}]==DivisorSigma[1, #+1]-(#+1)&]

CROSSREFS