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Search: id:A117461
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| A117461 |
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Indices associated with primes in A117460. Both primes and their indices, after calculation of their respective SOD's, bear the relationship that both are prime, and that SOD(i) < SOD(p) and SOD(p) is nextprime to SOD(i). |
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+0
2
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| 1, 2, 3, 14, 30, 43, 74, 142, 184, 214, 238, 241, 256, 287, 292, 308, 313, 346, 443, 449, 472, 544, 593, 601, 607, 623, 715, 737, 791, 814, 836, 854, 874, 881, 883, 913, 931, 973, 980, 995, 1088, 1156, 1237, 1307, 1316, 1343, 1381, 1396, 1462, 1565, 1622
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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A117458-A117459 is the opposite case where SOD(i) > SOD(p) A117460-A117461 is SOD(i) < SOD(p) A033548-A033549 is SOD(i) = SOD(p) G. L. Honaker, Jr.
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FORMULA
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SOD's are calculated for these indices; if they and their associated prime SOD's are both prime, and bear the relation in the Brief description above, they are added to the sequence.
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EXAMPLE
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a(4) = 30. Its associated prime is 113 with SOD = 5. SOD of a(4) = 3. Since 3 < 5, and 5 is nextprime to 3, a(4) belongs in the sequence.
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PROGRAM
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UBASIC 10 'use of str, mid, len, val 20 'in SOD prime index and SOD prime 30 Y=1 40 Y=nxtprm(Y) 50 C=C+1:print C; Y; "-"; 60 D=str(C):Z=str(Y) 70 E=len(D):F=len(Z) 80 for Q=2 to E 90 A=mid(D, Q, 1):G=val(A) 100 I=I+G:print I; 110 next Q 120 for R=2 to F 130 B=mid(Z, R, 1):H=val(B) 140 J=J+H:print J; 150 next R 160 if I=prmdiv(I) and J=prmdiv(J) and I<J and J=nxtprm(I) then stop 170 I=0:J=0 180 goto 40
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CROSSREFS
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Cf. A117460, A117458-A117459, A033548-A033549.
Sequence in context: A124663 A101005 A029998 this_sequence A047005 A080017 A042551
Adjacent sequences: A117458 A117459 A117460 this_sequence A117462 A117463 A117464
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KEYWORD
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easy,nonn,base
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AUTHOR
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Enoch Haga (Enokh(AT)comcast.net), Mar 18 2006
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