The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A340091 Odd numbers k such that A064989(k) is in A340151. 3
 679, 703, 1387, 1729, 1891, 2047, 2509, 2701, 2821, 3277, 3367, 5551, 7471, 7735, 8119, 8827, 9997, 10963, 11305, 12403, 13021, 13747, 13981, 14491, 14701, 15841, 16471, 17563, 19951, 21349, 21907, 21931, 22015, 23959, 24727, 25669, 26281, 27511, 28939, 29341, 31417, 32407, 38503, 39091, 39831, 39865, 40501, 41041 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Sequence A003961(A340151(i)), for i >= 1, sorted into ascending order. By definition, this has no common terms with A340077 nor any of its subsequences like A339869 or A339880. LINKS Antti Karttunen, Table of n, a(n) for n = 1..3290 PROG (PARI) A000265(n) = (n>>valuation(n, 2)); A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); }; A339904(n) = A000265(eulerphi(A003961(n))); A340075(n) = { my(u=A339904(n)); u/gcd(A003961(n)-1, u); }; A247074(n) = { my(f=factor(n)); eulerphi(f)/prod(i=1, #f~, gcd(f[i, 1]-1, n-1)); }; \\ From A247074 A340149(n) = A000265(A247074(A003961(n))); isA340151(n) = ((1!=A340075(n))&&(1==A340149(n))); A064989(n) = { my(f=factor(n)); if((n>1 && f[1, 1]==2), f[1, 2] = 0); for (i=1, #f~, f[i, 1] = precprime(f[i, 1]-1)); factorback(f) }; isA340091(n) = ((n%2)&&isA340151(A064989(n))); CROSSREFS Cf. A002997, A003961, A339869, A339880, A340077, A340151. Cf. A340092 (Carmichael numbers in this sequence). Sequence in context: A046514 A199995 A352263 * A164650 A200828 A097772 Adjacent sequences: A340088 A340089 A340090 * A340092 A340093 A340094 KEYWORD nonn AUTHOR Antti Karttunen, Dec 31 2020 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified November 28 06:02 EST 2023. Contains 367394 sequences. (Running on oeis4.)