A349864 Smallest k such that A349278(k) = n, or 0 if no such k exists.

1, 2, 3, 4, 5, 6, 7, 8, 9, 32, 0, 13, 0, 52, 23, 62, 0, 33, 0, 14, 43, 92, 0, 24, 0, 0, 63, 34, 0, 15, 0, 44, 83, 0, 25, 54, 0, 0, 0, 35, 0, 16, 0, 74, 45, 0, 0, 26, 0, 55, 0, 94, 0, 36, 65, 17, 0, 0, 0, 46, 0, 0, 27, 422, 85, 56, 0, 0, 0, 37, 0, 18, 0, 0, 0, 0, 47, 76, 0, 28, 603, 0, 0, 57, 0, 0, 0, 38, 0, 19

Offset

1,2

Comments

Composite numbers m for which a(m) = 0 are in A349865.

Links

Table of n, a(n) for n=1..90.

Formula

If p prime >= 11, a(p) = 0.

Example

a(10) = 32 since 2*(2+3) = 10 and no integer du < 32 gives u*(u+d) = 32.

Crossrefs

Cf. A349278, A349865.

Cf. A349732 (similar, with first digits).

Sequence in context: A225655 A024658 A358021 * A004849 A261279 A295638

Adjacent sequences: A349861 A349862 A349863 * A349865 A349866 A349867

Keyword

nonn,base

Author

Bernard Schott, Dec 03 2021

Extensions

a(64) and a(81) corrected by Michel Marcus, Dec 03 2021.

Status

approved