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A023572 Exponent of 2 in prime factorization of prime(n) - 3. 2
1, 2, 3, 1, 1, 4, 2, 1, 2, 1, 1, 3, 2, 1, 3, 1, 6, 2, 1, 2, 4, 1, 1, 1, 2, 3, 1, 1, 2, 7, 1, 3, 1, 2, 1, 5, 2, 1, 4, 1, 2, 1, 1, 2, 4, 2, 5, 1, 1, 2, 1, 3, 1, 2, 1, 2, 1, 1, 3, 1, 4, 2, 1, 1, 3, 1, 3, 1, 1, 2, 2, 1, 3, 2, 1, 1, 1, 1, 5, 1, 2, 1, 2, 3, 1, 1, 1, 2, 4, 2, 2, 3, 4, 2, 1, 1, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,2

LINKS

Robert Israel, Table of n, a(n) for n = 3..10000

MAPLE

seq(padic:-ordp(ithprime(n)-3, 2), n=3..100); # Robert Israel, Aug 21 2018

MATHEMATICA

Table[IntegerExponent[Prime[n]-3, 2], {n, 3, 100}] (* Jean-Fran├žois Alcover, Jun 03 2019 *)

PROG

(PARI) twos(n) = if(n%2==1||n<1, 0, twos(n/2)+1)

A023572(n) = twos(prime(n)-3)

(PARI) a(n) = valuation(prime(n)-3, 2); \\ Michel Marcus, Aug 21 2018

(MAGMA) [Valuation(NthPrime(n) - 3, 2): n in [3..100]]; // Vincenzo Librandi, Aug 21 2018

(Sage) [valuation(p-3, 2) for p in primes(5, 555)] # Peter Luschny, Aug 21 2018

CROSSREFS

Sequence in context: A059247 A244665 A194518 * A023570 A256989 A275214

Adjacent sequences:  A023569 A023570 A023571 * A023573 A023574 A023575

KEYWORD

nonn

AUTHOR

Clark Kimberling

EXTENSIONS

Offset set to 3 following a suggestion of R. J. Mathar, Peter Luschny, Aug 21 2018

STATUS

approved

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Last modified October 16 23:30 EDT 2019. Contains 328103 sequences. (Running on oeis4.)