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A301591 Primes p that have other solutions x to A023900(x) = A023900(p) than a power of p. 4
13, 37, 41, 61, 73, 89, 97, 109, 113, 157, 181, 193, 233, 241, 277, 281, 313, 337, 349, 353, 397, 401, 409, 421, 433, 449, 457, 461, 521, 541, 577, 593, 601, 613, 617, 641, 661, 673, 701, 733, 757, 761, 769, 821, 829, 877, 881, 929, 937, 953, 997, 1009, 1013, 1021, 1033, 1049 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

David A. Corneth, Table of n, a(n) for n = 1..10000

EXAMPLE

13 is a term because A023900(42) = A023900(13), where 42 is not a power of 13.

PROG

(PARI) f(n) = sumdivmult(n, d, d*moebius(d));

isok(p, vp) = {for (k=p+1, p^2-1, if (f(k) == vp, return (0)); ); return (1); }

lista(nn) = {forprime(p=2, nn, vp = f(p); if (!isok(p, vp), print1(p, ", ")); ); }

CROSSREFS

Cf. A001055, A023900, A301374.

Complement of A301590.

Sequence in context: A264908 A281004 A088963 * A301857 A220462 A280997

Adjacent sequences:  A301588 A301589 A301590 * A301592 A301593 A301594

KEYWORD

nonn

AUTHOR

Michel Marcus, Mar 24 2018

STATUS

approved

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Last modified July 12 20:45 EDT 2020. Contains 335669 sequences. (Running on oeis4.)