A348751 Numbers k for which A348750(k) < k.

2, 3, 5, 6, 7, 8, 10, 11, 13, 14, 15, 17, 18, 19, 21, 22, 23, 24, 26, 27, 29, 30, 31, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97

Offset

1,1

Links

Table of n, a(n) for n=1..81.

Prog

(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);

Crossrefs

Cf. A003961, A064989, A348750, A348751.

Cf. A348753 (corresponding 5-rough numbers, terms of A007310).

Sequence in context: A371731 A109423 A028801 * A348738 A239161 A162644

Adjacent sequences: A348748 A348749 A348750 * A348752 A348753 A348754

Keyword

nonn

Author

Antti Karttunen, Nov 02 2021

Status

approved