A323354 Odd n such that A015525(n) is not squarefree.

5, 15, 25, 35, 45, 51, 55, 65, 75, 85, 95, 105, 115, 125, 135, 145, 153, 155, 165, 175, 185, 195, 205, 215, 225, 235, 245, 255, 265, 275, 285, 295, 305, 315, 325, 335, 345, 355, 357, 365, 375, 385, 395, 405, 415, 425, 435, 445, 455, 459, 465, 475, 485

Offset

1,1

Links

Hugo Pfoertner, Table of n, a(n) for n = 1..5487

Example

a(1) = 5: A015525(5) = 361 = 19^2. All multiples of 5 are in the sequence and have 19^2 as a factor.
a(6) = 51: A015525(51) = 3005793749329960987137864733842257 = 17^2 * 67 * 307 *  624669523 * 809464558443747299.

Prog

(PARI) anm2=1; anm1=3; for(n=3, 155, an=3*anm1+8*anm2; anm2=anm1; anm1=an; if(n%2&&!issquarefree(an), print1(n, ", ")))

Crossrefs

Cf. A015525, A323353.

Sequence in context: A043509 A121025 A277592 * A172404 A031322 A017329

Adjacent sequences: A323351 A323352 A323353 * A323355 A323356 A323357

Keyword

nonn

Author

Hugo Pfoertner, Jan 12 2019

Status

approved