A392397 Primes p that are congruent to 1 (mod 10) for which 5 | A001177(p).

11, 31, 41, 61, 71, 101, 131, 151, 181, 191, 241, 251, 271, 311, 331, 401, 431, 491, 541, 571, 601, 631, 641, 661, 701, 751, 761, 811, 821, 911, 941, 971, 1021, 1051, 1061, 1091, 1151, 1171, 1181, 1201, 1231, 1291, 1301, 1321, 1361, 1381, 1451, 1471, 1481, 1531

Offset

1,1

Comments

Differs from A040969 by having the terms 11, 271, 431, ..., and not having the terms 281, 421, 461, ... .

This sequence is infinite (Panraksa and Tangboonduangjit, 2017, p. 27, Corollary 6.3).

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Chatchawan Panraksa and Aram Tangboonduangjit, On Some Arithmetic Properties of a Sequence Related to the Quotient of Fibonacci Numbers, The Fibonacci Quarterly, Vol. 55, No. 1 (2017), pp. 21-28.

Mathematica

A001177[n_] := Module[{k = 1}, While[!Divisible[Fibonacci[k], n], k++]; k];
q[p_] := Mod[p, 10] == 1 && Divisible[A001177[p], 5];
Select[Prime[Range[250]], q]

Prog

(PARI) A001177(n) = {my(k = 1); while(fibonacci(k) % n, k++); k; }
list(lim) = select(x -> x % 10 == 1 && !(A001177(x) % 5), primes(lim));

Crossrefs

Subsequence of A030430.

Cf. A001177, A040969.

Sequence in context: A327346 A030430 A059313 * A040975 A188384 A040172

Adjacent sequences: A392394 A392395 A392396 * A392398 A392399 A392400

Keyword

nonn

Author

Amiram Eldar, Jan 10 2026

Status

approved