A296142 -id:A296142 - cp's OEIS frontend

A366552 a(n) is the index of the first row of A296142 in which n appears, or 0 if n does not appear.

Original entry on oeis.org

0, 1, 104, 122, 0, 130, 3, 9, 103, 0, 119, 5, 11, 105, 0, 121, 7, 13, 107, 0, 123, 9, 15, 109, 0, 125, 11, 17, 111, 0

Offset: 1

Jeremy F. Alm, Oct 13 2023

a(5k) = 0 for all k, since no multiple of 5 appears in A296142.

Cf. A296142, A321351.

A321351 a(n) is the index of the row of A321350 in which n first appears, or zero if n does not appear.

Original entry on oeis.org

0, 1, 0, 26, 3, 0, 19, 5, 0, 21, 7, 0, 23, 9, 0, 25, 11, 0, 27, 13, 0, 29, 15, 0, 2, 17, 0, 4, 19, 0, 6, 21, 0, 8, 23, 0, 10, 25, 0, 12, 27, 0, 14, 29, 0, 16, 31, 0, 18, 33, 0, 20, 35, 0, 22

Offset: 1

Jeremy F. Alm, Nov 06 2018

No multiple of 3 appears, so a(3n) = 0 for all n.

			a(5) = 3, since in A321350, 2 --> (2+3)^2 --> 5, so 5 first appears in the third row.

Cf. A296142, A321350.

a(n) <= (2/3)*n + 15 for n > 6.

A321350 Triangle read by rows: first row is 2; given row k, define the elements of row k+1 to be the (sorted) elements derived from row k by two recursion rules: (i.) if x is in row k, then (x+3)^2 is in row k+1; (ii.) if x^2 is in row k, then x is in row k+1.

Original entry on oeis.org

2, 25, 5, 784, 28, 64, 619369, 8, 787, 961, 4489, 383621674384, 31, 67, 121, 619372, 624100, 929296, 20178064, 147165589059485451825769, 11, 790, 964, 1156, 4492, 4900, 15376, 383621674387, 383625390625, 389504554609, 863596631401, 407154387856489, 21657710603225344113280242498332241368243395984

Offset: 1

Jeremy F. Alm, Nov 06 2018

A variant of A296142, a sequence inspired by problem A1 on the 2017 William Lowell Putnam Mathematical Competition.

			First few rows are
2;
25;
5, 784;
28, 64, 619369;
8, 787, 961, 4489, 383621674384;
31, 67, 121, 619372, 624100, 929296, 20178064, 147165589059485451825769;
11, 790, 964, 1156, 4492, 4900, 15376, 383621674387, 383625390625, 389504554609, 863596631401, 407154387856489, 21657710603225344113280242498332241368243395984;

Cf. A296142, A321351.

cp's OEIS Frontend

A366552 a(n) is the index of the first row of A296142 in which n appears, or 0 if n does not appear.

Views

Author

Keywords

Comments

Crossrefs

A321351 a(n) is the index of the row of A321350 in which n first appears, or zero if n does not appear.

Views

Author

Keywords

Comments

Examples

Crossrefs

Formula

A321350 Triangle read by rows: first row is 2; given row k, define the elements of row k+1 to be the (sorted) elements derived from row k by two recursion rules: (i.) if x is in row k, then (x+3)^2 is in row k+1; (ii.) if x^2 is in row k, then x is in row k+1.

Views

Author

Keywords

Comments

Examples

Crossrefs