A272637 a(1)=1, a(2)=82; thereafter a(n) = squarefree part of a(n-1)+a(n-2).

1, 83, 21, 26, 47, 73, 30, 103, 133, 59, 3, 62, 65, 127, 3, 130, 133, 263, 11, 274, 285, 559, 211, 770, 109, 879, 247, 1126, 1373, 51, 89, 35, 31, 66, 97, 163, 65, 57, 122, 179, 301, 30, 331, 1, 83, 21, 26, 47, 73, 30, 103, 133, 59, 3, 62, 65, 127, 3, 130, 133, 263, 11, 274, 285, 559, 211, 770, 109, 879, 247, 1126, 1373, 51, 89, 35, 31, 66, 97, 163, 65, 57, 122, 179, 301, 30, 331

Offset

1,2

Comments

Periodic with period length 43. The period is [1, 83, 21, 26, 47, 73, 30, 103, 133, 59, 3, 62, 65, 127, 3, 130, 133, 263, 11, 274, 285, 559, 211, 770, 109, 879, 247, 1126, 1373, 51, 89, 35, 31, 66, 97, 163, 65, 57, 122, 179, 301, 30, 331].

References

Fred W. Helenius, Posting to Math Fun Mailing List, May 06 2016

Links

Table of n, a(n) for n=1..86.

Index entries for periodic sequences.

Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1).

Prog

(PARI) a(n)=[331, 1, 83, 21, 26, 47, 73, 30, 103, 133, 59, 3, 62, 65, 127, 3, 130, 133, 263, 11, 274, 285, 559, 211, 770, 109, 879, 247, 1126, 1373, 51, 89, 35, 31, 66, 97, 163, 65, 57, 122, 179, 301, 30][n%43+1] \\ Charles R Greathouse IV, May 28 2026

Crossrefs

Cf. A272636.

Sequence in context: A324674 A113890 A051327 * A317915 A033403 A174092

Adjacent sequences: A272634 A272635 A272636 * A272638 A272639 A272640

Keyword

nonn,easy

Author

N. J. A. Sloane, May 05 2016

Status

approved