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Search: id:A158652
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| A158652 |
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Any two consecutive digits in the sequence sum up to a prime. |
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+0
9
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| 1, 2, 3, 4, 7, 41, 43, 47, 49, 83, 85, 89, 202, 302, 303, 411, 412, 502, 503, 830, 2020, 2021, 2023, 2025, 2029, 2030, 2032, 3020, 3021, 4111, 4112, 5020, 5021, 6111, 6112, 9202, 9203, 20202, 30202, 30203, 41111, 41112, 50202, 50203, 83020, 202020
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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a(1)=1 and a(n) is always the smallest integer > a(n-1) not leading to a contradiction. Terms computed by Maximilian Hasler.
Comment from M. F. Hasler, Mar 24 2009: (Start) After the initial 2,3,4,7,41,43,47,49,83,85,89, the following pattern repeats:
202,302,303,
411,412,502,503,830,
2020,2021,2023,2025,2029,2030,2032,3020,3021,
4111,4112,5020,5021,6111,6112,9202,9203,
with each time two extra digits (either 02 or 11):
20202,30202,30203,
41111,41112,50202,50203,83020,
202020,202021,202023,202025,202029,202030,202032,302020,302021,
411111,411112,502020,502021,611111,611112,920202,920203,
and so on. (End)
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LINKS
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Robert G. Wilson, v, Table of n, a(n) for n=1..100
Eric Angelini, Chiffres consecutifs dans quelques suites
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MATHEMATICA
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f[s_List] := Block[{k = s[[ -1]] + 1, ls = Mod[ s[[ -1]], 10]}, While[ Union@ PrimeQ[ Plus @@@ Partition[ Join[{ls}, IntegerDigits@ k], 2, 1]] != {True}, k++ ]; Append[s, k]]; Nest[f, {1}, 45] [From Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 05 2009]
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CROSSREFS
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Cf. A152603-A152610.
Sequence in context: A052340 A094313 A070527 this_sequence A127074 A109617 A071373
Adjacent sequences: A158649 A158650 A158651 this_sequence A158653 A158654 A158655
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KEYWORD
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base,nonn
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AUTHOR
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Eric Angelini (eric.angelini(AT)skynet.be), Mar 23 2009
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