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A082075 First differences of primes with 4k+3 form, A002145. 3
4, 4, 8, 4, 8, 12, 4, 12, 8, 4, 8, 4, 20, 4, 20, 4, 8, 12, 12, 4, 12, 12, 8, 12, 12, 4, 12, 12, 12, 8, 12, 24, 4, 20, 16, 12, 8, 12, 4, 36, 12, 8, 4, 20, 4, 12, 8, 4, 8, 4, 20, 24, 16, 8, 16, 12, 8, 12, 12, 12, 4, 12, 24, 8, 28, 8, 12, 4, 8, 36, 24, 12, 4, 12, 20, 4, 20, 4, 20, 4, 8, 28, 20, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..84.

FORMULA

a(n)=[A002145(n+1)-A002145(n)]

EXAMPLE

first and second 4k+3 primes are 3 and 7, so a(1)=(7-3)=4;

MATHEMATICA

k=0; m=4; r=3; Do[s=Mod[Prime[n], m]; If[Equal[s, r], rp=ep; k=k+1; ep=Prime[n]; Print[ep-rp]; ], {n, 1, 1000}]

CROSSREFS

Cf. A002144, A002145, A082073-A082076.

Sequence in context: A273428 A273765 A273854 * A243641 A276620 A276681

Adjacent sequences:  A082072 A082073 A082074 * A082076 A082077 A082078

KEYWORD

nonn

AUTHOR

Labos Elemer, Apr 07 2003

STATUS

approved

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Last modified May 31 15:41 EDT 2020. Contains 334748 sequences. (Running on oeis4.)