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 A215641 Smallest prime whose decimal expansion consists of the concatenation of a 1-digit prime, a 2-digit prime, a 3-digit prime, ..., and an n-digit prime. 12
 2, 211, 211151, 2111011129, 211101100910009, 211101100910007100049, 2111011009100071000031000453, 211101100910007100003100000310000721, 211101100910007100003100000310000019100000543, 2111011009100071000031000003100000191000000071000000531 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS It is a plausible conjecture that a(n) always exists. a(n) has A000217(n) = n*(n+1)/2 digits. LINKS EXAMPLE a(4) = 2111011129, the smallest prime formed from a single-digit, a double-digit, a triple-digit, and a quadruple-digit prime, i.e., 2, 11, 101, 1129. CROSSREFS Cf. A000040, A000217, A003617. Subsequence of A195302. Cf. A338968 (similar with largest prime). Sequence in context: A167839 A107612 A068814 * A195335 A090560 A181903 Adjacent sequences:  A215638 A215639 A215640 * A215642 A215643 A215644 KEYWORD nonn,base AUTHOR Jonathan Vos Post, Aug 18 2012 EXTENSIONS Edited by N. J. A. Sloane, Aug 18 2012 STATUS approved

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Last modified May 9 07:36 EDT 2021. Contains 343692 sequences. (Running on oeis4.)