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A001092 Union of all numbers {p, q} where p and q are both primes or powers of primes and q = p+2. 0
1, 2, 3, 4, 5, 7, 9, 11, 13, 17, 19, 23, 25, 27, 29, 31, 41, 43, 47, 49, 59, 61, 71, 73, 79, 81, 83, 101, 103, 107, 109, 125, 127, 137, 139, 149, 151, 167, 169, 179, 181, 191, 193, 197, 199, 227, 229, 239, 241, 243, 269, 271, 281, 283, 311, 313, 347, 349, 359, 361, 419 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

REFERENCES

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 844.

LINKS

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].

PROG

(PARI) {isprimepower(n)=matsize(factor(n))[1]==1} for(n=1, 400, if(isprimepower(n)&&(isprimepower(n-2)||isprimepower(n+2)), print1(n", "))) (from Ralf Stephan, Aug 20 2004)

CROSSREFS

Cf. A053702, A074852.

Sequence in context: A063487 A081998 A074583 * A000430 A166684 A067126

Adjacent sequences:  A001089 A001090 A001091 * A001093 A001094 A001095

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jun 14, 2001

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Last modified February 16 07:39 EST 2012. Contains 205881 sequences.