A348752 Numbers k for which A348750(k) > k.

4, 9, 12, 16, 20, 25, 28, 32, 36, 48, 49, 64, 72, 80, 81, 100, 112, 116, 121, 128, 144, 162, 176, 180, 192, 196, 200, 208, 212, 225, 236, 240, 242, 243, 252, 256, 268, 272, 288, 300, 304, 320, 324, 336, 361, 384, 400, 405, 432, 441, 448, 450, 464, 468, 484, 496, 500, 512, 560, 567, 576, 588, 592, 596, 604, 625, 640

Offset: 1

Author

Antti Karttunen, Nov 02 2021

Keywords

• nonn

Crossrefs

Cf. A003961, A064989, A348750, A348751.

Cf. A348754 (corresponding 5-rough numbers, terms of A007310).

Programs

PARI

A003961(n) = my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); \\ From A003961
A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
A348750(n) = A064989(A064989(sigma(A003961(A003961(n)))));
isA348752(n) = (A348750(n)>n);