A109944 - OEIS

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A109944

a(1) = 1, a(n) = smallest prime number beginning with n if n is composite or vice versa. If n is prime a(n) = 10n.

0

1, 20, 30, 41, 50, 61, 70, 83, 97, 101, 110, 127, 130, 149, 151, 163, 170, 181, 190, 2003, 211, 223, 230, 241, 251, 263, 271, 281, 290, 307, 310, 3203, 331, 347, 353, 367, 370, 383, 397, 401, 410, 421, 430, 443, 457, 461, 470, 487, 491, 503, 5101, 521, 530, 541

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OFFSET

1,2

COMMENTS

If n is composite, a(n) = A018800(n). - David Wasserman, Jul 19 2005

LINKS

Table of n, a(n) for n=1..54.

CROSSREFS

Sequence in context: A072989 A216603 A166730 * A108030 A095787 A198471

Adjacent sequences: A109941 A109942 A109943 * A109945 A109946 A109947

KEYWORD

base,easy,nonn

AUTHOR

Amarnath Murthy, Jul 19 2005

EXTENSIONS

More terms from David Wasserman, Jul 19 2005

STATUS

approved