A351440 - OEIS

A351440

Numbers k for which A003958(sigma(k)) + A064989(sigma(k)) is equal to A003958(k) + A064989(k).

1, 6, 28, 496, 8128, 30240, 32760, 240408, 2178540, 6828720, 13042080, 23569920, 33550336, 42402048, 45532800, 142990848, 1379454720

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OFFSET

1,2

LINKS

PROG

(PARI)

A003958(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1]--); factorback(f); };

A064989(n) = { my(f = factor(n>>valuation(n, 2))); for(i=1, #f~, f[i, 1] = precprime(f[i, 1]-1)); factorback(f); };

isA351440(n) = { my(s=sigma(n)); ((A003958(s)+A064989(s)) == (A003958(n)+A064989(n))); };

CROSSREFS

Subsequence of A351446.

Subsequences: A000396, A336702.

KEYWORD

nonn,more

AUTHOR

STATUS

approved