A351548 a(n) = A349745(n) divided by 2 if it is even, and 0 if A349745(n) is odd.

0, 60, 108, 336, 1232, 11088, 114240, 261888, 320320, 418880, 2790720, 2882880, 3769920, 6499584, 9801792, 16930368, 19171152, 35672000, 47736000, 51068160, 98654400, 110046720, 172540368, 229909120, 403504640, 487788480, 738152448, 755415680, 886792320, 1960686000, 2070484416, 2339064000, 2889432000

Offset

1,2

Comments

Questions: Are all nonzero terms abundant (in A005101)? Are all terms even? Could either be proved? See also comments in A351538 and in A351549.

The terms a(2) .. a(52) are all also practical (A005153) and Zumkeller (A083207). - Antti Karttunen, Dec 05 2024

Links

Antti Karttunen, Table of n, a(n) for n = 1..52 (prepared from the b-file of A349745 computed by Amiram Eldar)

Index entries for sequences computed from indices in prime factorization

Index entries for sequences related to sigma(n)

Formula

a(n) = 0 if A349745(n) is odd, a(n) = A349745(n)/2 otherwise.

Prog

(PARI) A351548(n) = { my(u=A349745(n)); if(u%2, 0, u/2); };

Crossrefs

Cf. A005101, A005153, A083207, A326051 (all six known terms are present here), A329963, A349169, A349745, A351458, A351459, A351538.

Cf. also A351549.

Sequence in context: A258700 A008887 A217738 * A182683 A174601 A306908

Adjacent sequences: A351545 A351546 A351547 * A351549 A351550 A351551

Keyword

nonn

Author

Antti Karttunen, Feb 18 2022

Status

approved